refactor: replace isinstance narrowing with two except clauses in vumark

Catching (UnknownTargetError, TargetStatusNotSuccessError) in a dedicated
except clause means both types are already known to have target_id, so
no pylint no-member suppressions are needed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: adamtheturtle

src/vws_cli/vumark.py

@@ -58,18 +58,16 @@ def _handle_vumark_exceptions() -> Iterator[None]:
 
     try:
         yield
-    except (
-        VWSError,
-        ServerError,
-    ) as exc:
+    except (UnknownTargetError, TargetStatusNotSuccessError) as exc:
         if isinstance(exc, UnknownTargetError):
-            error_message = f'Error: Target "{exc.target_id}" does not exist.'  # pylint: disable=no-member
-        elif isinstance(exc, TargetStatusNotSuccessError):  # pragma: no cover
+            error_message = f'Error: Target "{exc.target_id}" does not exist.'
+        else:  # pragma: no cover
             error_message = (
-                f'Error: The target "{exc.target_id}" is not in the success '  # pylint: disable=no-member
+                f'Error: The target "{exc.target_id}" is not in the success '
                 "state and cannot be used to generate a VuMark instance."
             )
-        elif isinstance(exc, InvalidInstanceIdError):
+    except (VWSError, ServerError) as exc:
+        if isinstance(exc, InvalidInstanceIdError):
             error_message = "Error: The given instance ID is invalid."
         elif isinstance(exc, InvalidTargetTypeError):  # pragma: no cover
             error_message = (