Cannot create PRs in Bitbucket if branch deletion is disabled

[bkelley17]

How are you running Renovate?

Self-hosted Renovate

If you're self-hosting Renovate, tell us which platform (GitHub, GitLab, etc) and which version of Renovate.

bitbucket cloud

Please tell us more about your question or problem

When Renovate creates PRs in Bitbucket it sets close_source_branch: true. This indicates that you would like to delete the source branch after the PR is merged. https://github.com/renovatebot/renovate/blob/main/lib/modules/platform/bitbucket/index.ts#L928
This is a problem if branch restrictions disable the deletion of the source branch. (Settngs -> Branch Restrictions -> (branch pattern) -> Deleting this branch is not allowed) The PR creation fails with this error from Bitbucket You are restricted from closing the source branch.
Possibly this attribute could be omitted when making the PR creation call to BB, or else set to false.

Logs (if relevant)

No response

[rarkins]

Setting it to true benefits most users - the ones who don't have this restriction. My preference order would be:

1. Proactively detect such restrictions, then omit the setting, or
2. Intelligently catch the error, retry without the setting, ideally remember it (e.g. repo cache)

But why do you have such a setting, and what are the other implications? Does it mean branches can never be reused either? This will also cause problems with Renovate.