refactor(bitbucket-server): update runtime pr list

[RahulGautamSingh]

Changes

Update the pr list stored at runtime with new/updated info when a pr is updated.

Context

Ref: https://github.com/renovatebot/renovate/issues/32040

Documentation (please check one with an [x])

• [ ] I have updated the documentation, or
• [x] No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• [ ] Code inspection only, or
• [ ] Newly added/modified unit tests, or
• [x] No unit tests but ran on a real repository, or
• [ ] Both unit tests + ran on a real repository