Allow restarting of crashed a11y services

After an accessibility service crashes a few times in a short period
of time, framework would add it into a “blacklist”. User wouldn’t be
able to use (re-enable) it. If users express an intent in them working
again, we remove the crashed accessibility service from the blacklist.

Bug: 129689483
Test: a11y CTS & unit tests
Test: manual
      1. Install and enable an intentional crashed a11y service.
      2. After it's crashed and malfunctioning, re-enable it.
      3. Check if it's bound again.

Change-Id: Ia89121f11bc5e05fc829e0e3ecb266150409678b