Add flag not to enter ECBM in GSM and UMTS networks

Flag: com.android.internal.telephony.flags.disable_ecbm_based_on_rat
Bug: 389010789
Bug: 393978542
Test: VZW LTE E911 2.39
Test: Manual test - SRVCC(b/394203051)
Change-Id: Ie8f135235838fc33f9b124ae974c069d7d0b0694