[Backport 2.x] Replace legacy template with index template

[opensearch-trigger-bot]

Backport b69a364 from #1359

[codecov-commenter]

Codecov Report

Merging #1361 (46748bb) into 2.x (ecc7e91) will not change coverage.
The diff coverage is n/a.

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@@           Coverage Diff           @@
##              2.x    #1361   +/-   ##
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  Coverage   71.78%   71.78%           
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  Files          88       88           
  Lines        2027     2027           
  Branches      269      269           
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  Hits         1455     1455           
  Misses        509      509           
  Partials       63       63           

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[cliu123]

ResponseError: security_exception: [security_exception] Reason: no permissions for [indices:admin/index_template/put] and User [name=kibanaserver, backend_roles=[], requestedTenant=null]

This has been merged to security plugin 2.x branch. Re-building 2.x branch and publishing a new zip file to Maven repo should reflect the change and resolve this failure.

Merging this PR.