Live Update: Fix ChronometerStub/Chronometer cast crash

Live Update AOD Template was offloaded to the bg thread and Live Update
uses the same AOD template if notification layout is not changed.
Chronometer is an exceptional View among the views in Notification
because we inflate it when it's necessary. When the same view is
re-used with Chronometer case, existing logic will throw casting
exception and crash.

Fixes: 442583001
Flag: EXEMPT bug fix
Test: manual (Enable AOD, post a Live Update that uses Chronometer,
interact with chip. Observe no crash)

Change-Id: I2abfc35b76573db4386c7eb2b256f2037206e147