Provide context about why a cherry pick or revert failed

Adds additional context to the error message returned by the API when a commit fails to be cherry-picked or reverted.

Closes #33178 (closed)

2a224c88 - Update gitaly to ~> 1.70.0

7139d248 - Add support for create_tree_error_code from Gitaly

Available in Gitaly 1.70, this additional field on CreateTreeError provides context about why a cherry-pick or revert failed.

This adds an error_code attribute to Gitlab::Git::Repository::CreateTreeError.

85fd72fe - Add error_code attribute to ChangeError

Also adds an additional payload keyword argument to the BaseService#error method, which adds additional attributes to the result Hash.

bc57ad04 - Add error_code to cherry-pick/revert responses

57b7778a - Add error_code changelog entry

ad3b0b16 - Document error_code API response for pick/revert

88ea03f9 - Update operation_service_spec for error_code