[BitbucketLastCommit] Add Bitbucket last commit (#10043)

* Add Bitbucket last commit

* Update schemas

* Limit API results to 1

* Make `branch` a required path param

Co-authored-by: chris48s <chris48s@users.noreply.github.com>

* Better message for no commits found

* Update 404 message

* Use common `relativeUri` validator for `path`

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Co-authored-by: chris48s <chris48s@users.noreply.github.com>