Merge changes from topics "delegate_regi_new_state_losing_pdn", "ims_rcs_api_improvement_delegate_regi_state" am: a570a8259b am: d8d853ca17

Original change: https://android-review.googlesource.com/c/platform/packages/services/Telephony/+/1911014

Change-Id: I34c5d531279d3937edc885c3277f81840f658b1e