feat: improved git status for PublishPopover

[AdityaHegde]

Adding a check for git status for file system changes vs current branch and current branch vs primary branch. This avoids calling Merge unnesserily.

A follow up will add the rill dev modals for pulling changes from current branch to file system and pulling primary branch changes to current branch.

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!