[Backport 2.1] Replace legacy template with index template

[opensearch-trigger-bot]

Backport b69a364 from #1359

[peternied]

CI failures:

FAIL test/jest_integration/security_entity_api.test.ts (34.267 s)
...
    ResponseError: security_exception: [security_exception] Reason: no permissions for [indices:admin/index_template/put] and User [name=kibanaserver, backend_roles=[], requestedTenant=null]

FAIL test/jest_integration/multi_tenancy.test.ts (6.444 s)
...
    ResponseError: security_exception: [security_exception] Reason: no permissions for [indices:admin/index_template/put] and User [name=kibanaserver, backend_roles=[], requestedTenant=null]

[RyanL1997]

CI failures:

FAIL test/jest_integration/security_entity_api.test.ts (34.267 s)
...
    ResponseError: security_exception: [security_exception] Reason: no permissions for [indices:admin/index_template/put] and User [name=kibanaserver, backend_roles=[], requestedTenant=null]

FAIL test/jest_integration/multi_tenancy.test.ts (6.444 s)
...
    ResponseError: security_exception: [security_exception] Reason: no permissions for [indices:admin/index_template/put] and User [name=kibanaserver, backend_roles=[], requestedTenant=null]

Hi @peternied. This is the same error of 2.x branch before. It seems like the distribution build for this branch didn't have the backend change. Should we inform EE team to rebuild it?

Will re-approve, once the CI got fixed

[peternied]

Doesn't look like any progress is being made on this pull request, please comment if you'd like for this pull request to be reopened