[fenix] For https://github.com/mozilla-mobile/fenix/issues/13959: move resetAfter into StrictModeManager.
In a followup PR, we need to add state to strictModeManager (the
number of suppressions). This is much simpler to do when this is defined
as a class rather than an object. However, when this is defined as a
class, `resetAfter` needs access to the strictModeManager. Instead of
passing it in as an argument, it made sense to move this function onto
the strictModeManager instead.
Since folks are used to calling:
```
StrictMode.ThreadPolicy.allowThreadDiskReads().resetAfter
```
We're going to have to add a lint check to prevent them from doing that.
20 files changed: