[Sb refactor] Add OnSubscriptionsChanged input log

Helps us track when the OnSubscriptionsChanged listener was called,
which is the entrypoint for all of the mobile connections

Test: dumpsys
Bug: 273674238
Change-Id: I196212d1fbdbb7ea30baae5168f53cf1f6312be4

packages/SystemUI/src/com/android/systemui/statusbar/pipeline/mobile/data/MobileInputLogger.kt

@@ -179,6 +179,10 @@ constructor(
     fun logDefaultMobileIconGroup(group: SignalIcon.MobileIconGroup) {
         buffer.log(TAG, LogLevel.INFO, { str1 = group.name }, { "defaultMobileIconGroup: $str1" })
     }
+
+    fun logOnSubscriptionsChanged() {
+        buffer.log(TAG, LogLevel.INFO, {}, { "onSubscriptionsChanged" })
+    }
 }
 
 private const val TAG = "MobileInputLog"

packages/SystemUI/src/com/android/systemui/statusbar/pipeline/mobile/data/repository/prod/MobileConnectionsRepositoryImpl.kt

@@ -129,6 +129,7 @@ constructor(
         val callback =
             object : SubscriptionManager.OnSubscriptionsChangedListener() {
                 override fun onSubscriptionsChanged() {
+                    logger.logOnSubscriptionsChanged()
                     trySend(Unit)
                 }
             }