Revert "Expose getSubId to ensure we have correct subId state in IMS"

Revert "Enforce the subId of a request matches the active subId ..."

Revert submission 16908142-enforce_subId

Reason for revert: b/217748245
Reverted Changes:
Ie9838dde5:Expose getSubId to ensure we have correct subId st...
I4ec85c201:Enforce the subId of a request matches the active ...

Change-Id: I015e2e6dd3e7a12e282a4c8aaaa9a3e5324a8ffd