Search API bugs

[aniketkatkar97]

Affected module
Backend

Describe the bug

1. /aggregate API does not return all possible suggestions when some text is passed as value for displayName.keyword. This is especially when there are capital letters present in the display name.
   example request: /api/v1/search/aggregate?index=database_search_index%2Cdatabase_schema_search_index%2Ctable_search_index%2Cstored_procedure_search_index&field=displayName.keyword&value=.%2ADim.%2A&q=%7B%22query%22%3A%7B%22bool%22%3A%7B%7D%7D%7D

Screen.Recording.2024-09-12.at.10.16.28.PM.mov

2. There is a mismatch between the index_count and the list of entities for API collections and API endpoints data assets

Screen.Recording.2024-09-13.at.9.53.23.AM.mov

3. In case the display name is absent for entities fallback to name in ES, same as we do for tables
   

Version:

• OS: [e.g. iOS]
• Python version:
• OpenMetadata version: [e.g. 0.8]
• OpenMetadata Ingestion package version: [e.g. openmetadata-ingestion[docker]==XYZ]

Additional context
Add any other context about the problem here.

[harshach]

2&3 are addressed in this PR #17871