Raise AvailabilitySettingsPanel bundle baseline for the probe-attribution UI

c2c51019d grew the chunk to 7.08 kB gzip, past the 15% headroom over
the 5.94 kB baseline, which has failed the bundle budget on every main
push since. The growth is the intentional probe assignment and source
attribution feature, so re-baseline at the measured size.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend-modern/.bundlesize.json

@@ -92,7 +92,7 @@
       "baselineGzip": 6712
     },
     "AvailabilitySettingsPanel": {
-      "baselineGzip": 6085
+      "baselineGzip": 7250
     },
     "SecurityAuthPanel": {
       "baselineGzip": 5836