Update remap_disconnect_cause_sip_request_cancelled flag to be exported.

This CL ensures that the Telephony flag remap_disconnect_cause_sip_request_cancelled is exported. It also removes an unnecessary duplicate definition that defines  simultaneous_calling_indications as exported as well.

Bug: 351258918
Flag: EXEMPT resource only update
Test: N/A flag change only
Change-Id: Ia67d40b7f007c9bf7ef2dbe4f2ba307ce45efbe7