Remove "Update to the <version> release branch in the distribution manifest" step from plugin repo release checklist

[msfroh]

In the plugin repo release checklist (e.g. opensearch-project/dashboards-search-relevance#253), there is a step "Update to the release branch in the distribution manifest".

I created a PR to do that #3978 just a couple of minutes after @gaiksaya updated all the repos to the 2.10 release branch in #3977.

I love that all the repos were switched in a single PR (thanks @gaiksaya!), but we should probably remove that step from the checklist for the next release. (I lost 2 whole minutes making my change and posting a PR!)

[gaiksaya]

Adding the template that creates those issues and needs change https://github.com/opensearch-project/opensearch-build/blob/main/.github/ISSUE_TEMPLATE/component_release_template.md