Add FLAG_IMMUTABLE to PendingIntent in LegacyModeSmsHandler.

Bug: 185126549, 185126319
Test: manual.

Merged-In: I1024353434674f8e4bf164c3a6c1e16924dfaa8f
Change-Id: I3b015de3187f45096235313e8d39a3c3f1b768b7
1 file changed