[Cleanup] any type if possible

[kavilla]

Describe the bug

During the Node upgrade, we began to start seeing linter complaints about types being implicitly typed as any. To get around that we explicitly typed them as any. However some files were missed when updated to explicitly typed:

For example:

• https://github.com/opensearch-project/OpenSearch-Dashboards/blob/main/src/plugins/data/public/search/aggs/aggs_service.ts#L154
• https://github.com/opensearch-project/OpenSearch-Dashboards/blob/main/src/plugins/data/public/ui/query_string_input/fetch_index_patterns.ts#L53
• https://github.com/opensearch-project/OpenSearch-Dashboards/blob/main/src/plugins/data/server/search/aggs/aggs_service.ts#L133

To Reproduce
Navigate to those files, notice the linter complain.

Expected behavior
The solution to type as any was a temp fix we should explicitly type it as the expected type if possible.