[BUG] Import of the opensearch_index resource does not include the analysis attributes

[gonz-cint]

What is the bug?

When importing an opensearch_index resource using the OpenSearch provider for Terraform, the analysis attributes (e.g., analysis_analyzer, analysis_tokenizer, analysis_filter, analysis_char_filter) are not included in the state of the imported resource. As a result, Terraform sees these as differences and forces the resource to be replaced during the next plan/apply cycle.

How can one reproduce the bug?

1- Create an OpenSearch index resource with analysis attributes (e.g., analyzers, tokenizers, filters).
2- Import the resource using the OpenSearch provider for Terraform (terraform import or the import block).
3- Run terraform state show on the imported resource and notice that the analysis attributes are missing.
4- Run terraform plan to compare the imported resource against the configuration, and observe that Terraform plans to replace the resource because the analysis attributes are seen as missing.

What is the expected behavior?

When importing an OpenSearch index resource, all attributes, including analysis attributes, should be correctly imported into the state. Terraform should not force replacement of the resource if the imported resource matches the configuration.

What is your host/environment?

Terraform version: 1.8.5
OpenSearch provider version: 2.3.1
OpenSearch version: 2.13

Do you have any additional context?

The following index was imported into the state running terraform import:

Configuration Block:

resource "opensearch_index" "example" {
  name                 = "example-index"
  number_of_shards     = 1
  number_of_replicas   = 0
  analysis_analyzer    = file("analyzers.json")
  analysis_tokenizer   = file("tokenizers.json")
  analysis_filter           = file("filters.json")
  analysis_char_filter = file("char_filters.json")
}

the analysis objects do exist in the resource already, however after importing this is the output of terraform state show:

resource "opensearch_index" "example" {
  id                 = "example-index"
  name               = "example-index"
  number_of_shards   = 1
  number_of_replicas = 0
}

Therefore a plan triggers an index replacement, as it sees the analysis objects as additions:

  # opensearch_index.example must be replaced
- resource "opensearch_index" "example" {
    analysis_analyzer    = ...
    analysis_tokenizer   = ...
    analysis_filter      = ...
    analysis_char_filter = ...
    ...
}