Match timestamps without year in pipeline tests with regex (#4984)

- Timestamps that are parsed without a year (such as those on BSD-style
syslog messages) will have their expected values inherit the year the
expected files are generated in. This means that tests will only pass
in the year that the expected files are generated.
- The relevant timestamp field (@timestamp, for example) has been added
to the pipeline test config as a dynamic field, and a regex pattern is
used to match the expected format of the timestamp.

packages/cisco_aironet/data_stream/log/_dev/test/pipeline/test-common-config.yml

@@ -1,3 +1,5 @@
+dynamic_fields:
+  "@timestamp": "^[0-9]{4}(-[0-9]{2}){2}T[0-9]{2}(:[0-9]{2}){2}\\.[0-9]{3}"
 fields:
   tags:
     - preserve_original_event

packages/cisco_ftd/data_stream/log/_dev/test/pipeline/test-common-config.yml

@@ -1,3 +1,5 @@
+dynamic_fields:
+  "@timestamp": "^[0-9]{4}(-[0-9]{2}){2}T[0-9]{2}(:[0-9]{2}){2}\\.[0-9]{3}"
 fields:
   tags:
     - preserve_original_event

packages/cisco_ios/data_stream/log/_dev/test/pipeline/test-common-config.yml

@@ -1,5 +1,6 @@
 dynamic_fields:
   event.ingested: ".*"
+  "@timestamp": "^[0-9]{4}(-[0-9]{2}){2}T[0-9]{2}(:[0-9]{2}){2}\\.[0-9]{3}"
 fields:
   tags:
     - preserve_original_event

packages/cisco_ise/data_stream/log/_dev/test/pipeline/test-common-config.yml

@@ -1,3 +1,5 @@
+dynamic_fields:
+  "@timestamp": "^[0-9]{4}(-[0-9]{2}){2}T[0-9]{2}(:[0-9]{2}){2}\\.[0-9]{3}"
 fields:
   tags:
     - preserve_original_event

packages/cisco_secure_email_gateway/data_stream/log/_dev/test/pipeline/test-common-config.yml

@@ -1,3 +1,5 @@
+dynamic_fields:
+  "@timestamp": "^[0-9]{4}(-[0-9]{2}){2}T[0-9]{2}(:[0-9]{2}){2}\\.[0-9]{3}"
 fields:
   tags:
     - preserve_original_event

packages/infoblox_nios/data_stream/log/_dev/test/pipeline/test-common-config.yml

@@ -1,3 +1,6 @@
+dynamic_fields:
+  "event.created": "^[0-9]{4}(-[0-9]{2}){2}T[0-9]{2}(:[0-9]{2}){2}\\.[0-9]{3}"
+  "@timestamp": "^[0-9]{4}(-[0-9]{2}){2}T[0-9]{2}(:[0-9]{2}){2}\\.[0-9]{3}"
 fields:
   tags:
     - preserve_original_event

packages/pfsense/data_stream/log/_dev/test/pipeline/test-common-config.yml

@@ -1,3 +1,5 @@
+dynamic_fields:
+  "@timestamp": "^[0-9]{4}(-[0-9]{2}){2}T[0-9]{2}(:[0-9]{2}){2}\\.[0-9]{3}"
 fields:
   tags:
     - preserve_original_event

packages/symantec_endpoint/data_stream/log/_dev/test/pipeline/test-common-config.yml

@@ -1,3 +1,5 @@
+dynamic_fields:
+  "@timestamp": "^[0-9]{4}(-[0-9]{2}){2}T[0-9]{2}(:[0-9]{2}){2}\\.[0-9]{3}"
 fields:
   tags:
     - forwarded

packages/zscaler_zia/data_stream/alerts/_dev/test/pipeline/test-common-config.yml

@@ -1,3 +1,5 @@
+dynamic_fields:
+  "@timestamp": "^[0-9]{4}(-[0-9]{2}){2}T[0-9]{2}(:[0-9]{2}){2}\\.[0-9]{3}"
 fields:
   tags:
     - preserve_original_event