Add FLAG_IMMUTABLE to PendingIntent in LegacyModeSmsHandler. Bug: 185126549, 185126319 Test: manual. Merged-In: I1024353434674f8e4bf164c3a6c1e16924dfaa8f Change-Id: I3b015de3187f45096235313e8d39a3c3f1b768b7 (cherry picked from commit bdd6d1ea00f94296c251f4340a52a2035167370b) Merged-In:I3b015de3187f45096235313e8d39a3c3f1b768b7