Implement option to not remove auto-added reviewers in a Pull request when having the reset reviewers merge check enabled

Currently in Bitbucket Cloud, when having the merge check “Reset approvals when the source branch is modified“ enabled, the pull request reviewers that were auto-added because they used the Approval button/Requested changes get removed from the reviewers list when there is an update in the source branch of the pull request (new commit)

Steps to reproduce :

• Create a Pull Request with no reviewers. The repository should have branch restrictions with the merge check “Reset approvals when the source branch is modified“ enabled

• Ask a user to approve the pull request or request changes. The user will be auto-added as a reviewer

• Push a new change to the source branch of the pull request

• The approvals will be reset, and all the reviewers that were auto-added by previous approvals will be removed from the PR.

The same does not happen if the reviewer is manually added using the "+ Add Reviewer" button in the left side-card of pull request, or if the reviewers are added during the pull request creation page.

This feature request is for auto-added reviewers to not get removed from the PR when the merge check is enabled (the approvals should still be reset, but the auto-added reviewers should be kept as reviewers of the PR).