fix(bitbucket): Resolve mypy errors in get_repositories

Type the username property return and rename a shadowed variable to
fix arg-type, no-redef, and return-value errors caught by CI.

Author: jaydgoss

src/sentry/integrations/bitbucket/integration.py

@@ -140,14 +140,14 @@ def get_repositories(
     ) -> list[RepositoryInfo]:
         username = self.model.metadata.get("uuid", self.username)
         if not query:
-            repos = self.get_client().get_repos(username, page_number_limit=page_number_limit)
+            all_repos = self.get_client().get_repos(username, page_number_limit=page_number_limit)
             return [
                 {
                     "identifier": repo["full_name"],
                     "name": repo["full_name"],
                     "external_id": self.get_repo_external_id(repo),
                 }
-                for repo in repos
+                for repo in all_repos
             ]
 
         client = self.get_client()
@@ -215,7 +215,7 @@ def extract_source_path_from_source_url(self, repo: Repository, url: str) -> str
     # Bitbucket only methods
 
     @property
-    def username(self):
+    def username(self) -> str:
         return self.model.name