Use Bundle to access Global.Settings values

While making the Developer Options changes, the app startup time was
increased due to reading the Global.Settings values incorrectly. As Cody
had already determined, we need to use the Bundle.getString() values,
rather than reading them from the Context. This change re-introduces
that fix.

Based on b/120784945, I'm looking at the 'bindApplication' values that's
output from the following test:

$ atest -it google/perf/app-startup/benchmark-app-hermetic/cold-dropcache-test --verbose

Without this fix:
  bindApplication: 22.67
  bindApplication: 21.47
  bindApplication: 19.40

With this fix:
  bindApplication: 16.67
  bindApplication: 16.33
  bindApplication: 16.67

Based on the above values, this appears to recover the missing time.

Bug: 120784945
Test: Verify app startup time is reduced.
Test: Verify ANGLE can still be enabled/disabled with the
Global.Settings values.
Test: Verify CtsAngleIntegrationHostTestCases passes.

Change-Id: I0435702c3708c8566e94673dd3a2a40eb8253052