Don't keep parceled extras for history broadcasts.

On dumpsys we do show history broadcast intents with extras, but
if an intent's extras are still parceled, we can't show anything
(but the length) anyway, so let's just remove them, because sometimes
they contain heavy objects such as bitmaps.

Bug: 62144301
Test: manual tests: Boot, add account start apps, insert SIM
Change-Id: Ia64dd46d66fba3098e32c435509f4940ae978710