Added subscriptions dump to connectivity bugreport

The subscription bump has been moved out of TelephonyDebugService
dump because of it has been included in the bugreport through
isub service dump. This caused the regression when collecting
the connectivity dump through BugreportManager.startConnectivityBugreport.

Fixed by adding it DumpstateTelephonyOnly.

Fix: 273805171
Test: atest android.bugreport.cts.BugreportManagerTest#testTelephonyBugreport
      and verified SubscriptionManagerService dump shown in the
      bugreport.
Change-Id: I43269b24f73edabdaff8f6af8aef3a0bda5ad67b