fix(connection): delete the unreachable duplicated label-drain body (t62 F2)

`_sweep_labels` ended with `return cached`, and the whole body of
`_drain_app_label_requests` — its docstring, the queue check, the fetch task —
followed it at the same indent level. Valid Python, never executed, and
invisible to every gate: the sweep, ruff and the stub suite all pass over it.
This is the second shipped artefact of its kind (an earlier review found a
duplicated statement), so the mechanism lands in the drift sweep next; here the
dead copy goes.

The `; echo __NSH_EXIT:$?` marker in `_dump_label` is documented while it is
touched (t62 nit b): it sits after a `head` pipeline, Android's sh has no
PIPESTATUS, so `$?` is head's status and never the dump's. Nothing reads its
VALUE — the parser strips the line — and the property that matters is that a
command which RAN leaves non-blank output, which is what separates "ran, no
label" (a cached negative) from "the transport delivered nothing" (a retry).

custom_components/nvidia_shield/connection.py

@@ -694,6 +694,15 @@ class ShieldConnectionManager:
 
         Returns the label (possibly "") when the dump RAN, and None when it did
         not run or delivered no output at all.
+
+        The exit marker is a liveness tell, not a status code (t62 nit b): it sits
+        after a ``head`` pipeline, and the Android shell that runs this has no
+        PIPESTATUS, so ``$?`` is ``head``'s status rather than the dump's. Nothing
+        reads its VALUE — ``parse_application_label`` strips the marker line — and
+        the only property tested here is that a command which RAN leaves non-blank
+        output even when the device prints no label. That non-blankness is what
+        separates "ran, no label" from "the transport delivered nothing", which
+        this method turns into a cached negative versus a retry.
         """
         poller = self._poller
         if poller is None or not self.connected:
@@ -1110,15 +1119,6 @@ class ShieldConnectionManager:
         return cached
 
 
-        """Start at most one label fetch per watchdog cycle."""
-        if not self._app_label_requests or self._poller is None:
-            return
-        package = min(self._app_label_requests)
-        self._app_label_requests.discard(package)
-        self._tasks.append(
-            self._create_task(self._fetch_app_label(package), f"app_label_{package}")
-        )
-
     def _drain_app_label_requests(self) -> None:
         """Start at most one label fetch per watchdog cycle."""
         if not self._app_label_requests or self._poller is None: