Include index mode per index in `GET /_resolve/index/*` API response

[vadimkibana]

Description

Sometimes Kibana needs to know which ES indices are "TSDB", for example, to show them in METRICS ES|QL command autocomplete. Currently, the most efficient way to fetch such list is to first query for all indices using the GET /_resolve/index/* call and then loop through each index and execute GET /<index>/_settings for each index.

Instead, provide index mode metadata directly in the GET /_resolve/index/* API response, so that GET /<index>/_settings does not need to be called for each index.

[elasticsearchmachine]

Pinging @elastic/es-storage-engine (Team:StorageEngine)

[elasticsearchmachine]

Pinging @elastic/es-data-management (Team:Data Management)

[lkts]

Do you have a preference for how this will be presented in the response? I can see that we have attributes in the response now. Should we add an attribute for each mode or should we add a new section (maybe settings) to response?