[MDS][Enhancement] Deprecate the non-MDS data connection endpoint for direct query data source

[RyanL1997]

Description

In version 2.16, the migration of direct query data source was done in data source management plugin. For supporting MDS, it originally has 2 versions of same endpoints, such as,

• /api/directquery/dataconnections
  and
• /api/directquery/dataconnections/dataSourceMDSId={dataSourceMDSId?},
  for with and without MDS support.

The 2 versions of endpoints are served the same purpose. The non-mds endpoints is only being used when MDS feature flag is disabled- for local cluster only environment. so that the best practice is to unified the usage and deprecate the non-mds version, since the mds endpoints are also supporting local cluster calls by passing in the '' as cluster ID.

OpenSearch Version

2.16 +

Dashboards Version**

2.16 +

Plugins

OSD core - data source management

Reference

• Migration PR: [MDS] Observability Datasource Plugin migration with MDS support #7143
• data_connections_router class: https://github.com/opensearch-project/OpenSearch-Dashboards/blob/9eae14851672fad87d077856c2af47a8e181b671/src/plugins/data_source_management/server/routes/data_connections_router.ts
• sample usage of non-mds data connection endpoint:

  OpenSearch-Dashboards/src/plugins/data_source_management/public/components/utils.ts

  Line 65 in 9eae148

  const res = await http.get(`${DATACONNECTIONS_BASE}`);