[Bug]: Release branch needs to be cut minutes before generating first RC

[gaiksaya]

Describe the bug

Coming from #4909 (comment)
Creating release branch early requires last minute PRs to be backported to the release branch. For 2.17.0 the count was pretty high and considering heavy CI check such as gradle check it took significant amount of time.

To reproduce

See the release candidate date postponed here: https://opensearch.org/releases.html for 2.17.0

Expected behavior

Branch should be cut minutes before first RC

Screenshots

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Host / Environment

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Additional context

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Relevant log output

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