Fix out-of-date doc about app op default mode.

: Throw a `SecurityException` on access. This can be suppressed by using a `...noThrow` method to

check the mode

The initial state of an app-op is defined in `AppOpsManager.sOpDefaultMode`. Confusingly the

initial state is often not `MODE_DEFAULT`

The initial state of an app-op is defined in its `AppOpInfo`. Confusingly the initial state is not

always `MODE_DEFAULT`, if `AppOpInfo.Builder.setDefaultMode()` is called with a different mode.

Per-package modes can be set using `AppOpsManager.setMode` and per-uid modes can be set using

`AppOpsManager.setUidMode`.