[Maintenance] Back-port branches not getting deleted

[navneet1v]

Issue

Whenever a PR needs to be backported to 2.x branch we add a label : backport-2.x to that PR. Due to this its creates a backport branch like backport/backport-2058-to-2.17. There is a GH action: https://github.com/opensearch-project/k-NN/blob/main/.github/workflows/delete_backport_branch.yml which was supposed to delete this branch, but that GH action is failing(https://github.com/opensearch-project/k-NN/actions/workflows/delete_backport_branch.yml) and hence branches are not getting deleted. This issue tracks the fix for that GH action.

Fix: opensearch-project/OpenSearch@3a1b6d1

[0ctopus13prime]

Will work on this.