Fixed crash in subscription controller

Added null pointer check when no active subscription info
is returned.

Test: Telephony sanity tests
Bug: 77695179
Merged-In: Ifcab0f57eff5cf7e89421f0c4d378f112eadb073
Change-Id: Ifcab0f57eff5cf7e89421f0c4d378f112eadb073
(cherry picked from commit 33814154)