refactor: make related code closer

cube_doctor/__init__.py

@@ -388,8 +388,6 @@ class Command:
                 print(f"ERROR: {cube.name} is EMPTY, skip it")
                 continue
 
-            branches = [x.name for x in cube.branches.list(all=True)]
-
             if forced_branch_name is not None:
                 if not forced_branch_name.startswith("topic/default/"):
                     forced_branch_name = "topic/default/" + forced_branch_name
@@ -399,6 +397,8 @@ class Command:
             else:
                 target_branch = None
 
+            branches = [x.name for x in cube.branches.list(all=True)]
+
             # we already sent the MR
             if (
                 not update_mr