[Backport 2.16] Template Creation using Context

[mgodwan]

Backport of #14811

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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[github-actions]

❕ Gradle check result for 7f924b8: UNSTABLE

• TEST FAILURES:

      1 org.opensearch.repositories.azure.AzureBlobContainerRetriesTests.testWriteLargeBlob

Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[codecov]

Codecov Report

Attention: Patch coverage is 73.91304% with 42 lines in your changes missing coverage. Please review.

Project coverage is 71.59%. Comparing base (a3a4aa9) to head (7f924b8).
Report is 1 commits behind head on 2.16.

Files	Patch %	Lines
.../java/org/opensearch/cluster/metadata/Context.java	67.34%	14 Missing and 2 partials ⚠️
...r/applicationtemplates/SystemTemplateMetadata.java	20.00%	6 Missing and 2 partials ⚠️
...plicationtemplates/TemplateRepositoryMetadata.java	0.00%	6 Missing ⚠️
...arch/cluster/metadata/ComposableIndexTemplate.java	75.00%	1 Missing and 3 partials ⚠️
...cluster/metadata/MetadataIndexTemplateService.java	94.11%	2 Missing and 1 partial ⚠️
...ate/post/TransportSimulateIndexTemplateAction.java	0.00%	2 Missing ⚠️
...template/post/TransportSimulateTemplateAction.java	0.00%	2 Missing ⚠️
...ch/cluster/coordination/OpenSearchNodeCommand.java	0.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               2.16   #14957      +/-   ##
============================================
+ Coverage     71.55%   71.59%   +0.04%     
- Complexity    62686    62750      +64     
============================================
  Files          5120     5121       +1     
  Lines        294256   294402     +146     
  Branches      42880    42903      +23     
============================================
+ Hits         210543   210775     +232     
+ Misses        66092    65955     -137     
- Partials      17621    17672      +51     

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