Templates installed from integration package are missing dynamic templates

[axw]

APM Server version (apm-server version):

6d06e68

Description of the problem including expected versus actual behavior:

When running under Fleet, templates are missing the APM-specific dynamic templates for labels.

Steps to reproduce:

• Install APM package, assign to a policy and agent
• Send some APM data to the agent
• Check the index template mappings

In the mappings, the dynamic templates will look like

"dynamic_templates": [
    {
      "strings_as_keyword": {
        "mapping": {
          "ignore_above": 1024,
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    }
  ]

They should look like (ignore duplicates, that's #4576)

"dynamic_templates": [
    {
      "labels": {
        "path_match": "labels.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    },
    {
      "container.labels": {
        "path_match": "container.labels.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    },
    {
      "fields": {
        "path_match": "fields.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    },
    {
      "docker.container.labels": {
        "path_match": "docker.container.labels.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    },
    {
      "kubernetes.labels.*": {
        "path_match": "kubernetes.labels.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "*"
      }
    },
    {
      "kubernetes.annotations.*": {
        "path_match": "kubernetes.annotations.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "*"
      }
    },
    {
      "labels_string": {
        "path_match": "labels.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    },
    {
      "labels_boolean": {
        "path_match": "labels.*",
        "mapping": {
          "type": "boolean"
        },
        "match_mapping_type": "boolean"
      }
    },
    {
      "labels_*": {
        "path_match": "labels.*",
        "mapping": {
          "scaling_factor": 1000000,
          "type": "scaled_float"
        },
        "match_mapping_type": "*"
      }
    },
    {
      "labels_string": {
        "path_match": "labels.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    },
    {
      "labels_boolean": {
        "path_match": "labels.*",
        "mapping": {
          "type": "boolean"
        },
        "match_mapping_type": "boolean"
      }
    },
    {
      "labels_*": {
        "path_match": "labels.*",
        "mapping": {
          "scaling_factor": 1000000,
          "type": "scaled_float"
        },
        "match_mapping_type": "*"
      }
    },
    {
      "labels_string": {
        "path_match": "labels.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    },
    {
      "labels_boolean": {
        "path_match": "labels.*",
        "mapping": {
          "type": "boolean"
        },
        "match_mapping_type": "boolean"
      }
    },
    {
      "labels_*": {
        "path_match": "labels.*",
        "mapping": {
          "scaling_factor": 1000000,
          "type": "scaled_float"
        },
        "match_mapping_type": "*"
      }
    },
    {
      "labels_string": {
        "path_match": "labels.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    },
    {
      "labels_boolean": {
        "path_match": "labels.*",
        "mapping": {
          "type": "boolean"
        },
        "match_mapping_type": "boolean"
      }
    },
    {
      "labels_*": {
        "path_match": "labels.*",
        "mapping": {
          "scaling_factor": 1000000,
          "type": "scaled_float"
        },
        "match_mapping_type": "*"
      }
    },
    {
      "labels_string": {
        "path_match": "labels.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    },
    {
      "labels_boolean": {
        "path_match": "labels.*",
        "mapping": {
          "type": "boolean"
        },
        "match_mapping_type": "boolean"
      }
    },
    {
      "labels_*": {
        "path_match": "labels.*",
        "mapping": {
          "scaling_factor": 1000000,
          "type": "scaled_float"
        },
        "match_mapping_type": "*"
      }
    },
    {
      "transaction.marks": {
        "path_match": "transaction.marks.*",
        "mapping": {
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    },
    {
      "transaction.marks.*.*": {
        "path_match": "transaction.marks.*.*",
        "mapping": {
          "scaling_factor": 1000000,
          "type": "scaled_float"
        },
        "match_mapping_type": "*"
      }
    },
    {
      "strings_as_keyword": {
        "mapping": {
          "ignore_above": 1024,
          "type": "keyword"
        },
        "match_mapping_type": "string"
      }
    }
  ],