Release docs workflow is not idempotent

[vinayada1]

Describe the bug

There was some issue with release tags and therefore the workflow run to release docs failed. The tags issue was resolved separately but now the release docs workflow fails with the following error:-
++ git push origin v0.30
To https://github.com/radius-project/docs
! [rejected] v0.30 -> v0.30 (fetch first)
error: failed to push some refs to 'https://github.com/radius-project/docs'
hint: Updates were rejected because the remote contains work that you do not
hint: have locally. This is usually caused by another repository pushing to
hint: the same ref. If you want to integrate the remote changes, use
hint: 'git pull' before pushing again.

https://github.com/radius-project/docs/actions/runs/7760931535/job/21168287608

Steps to reproduce

1. Release docs workflow fails (due to any reason)
2. Re-run the workflow and it requires 0.30 release branch to be deleted

Expected behavior

A re-run of the release docs workflow should be idempotent and not require the older release branch to be deleted

Screenshots

Desktop (please complete the following information):

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Smartphone (please complete the following information):

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Additional context

This was encountered during v0.30.0 release

AB#11109