[TIMOB-27555] Allow PRs to be tagged with label to enable more exhaustive testing

We should enable a way to flag specific PRs so that more exhaustive testing is performed. We have been playing with changing deploy types used by the test suite, as well as adding iPad Simulator recently. But we haven't formalized what exact matrix of testing should occur regularly on PRs or master. We run tests on 3 android devices on master builds. We have no iOS devices running on any build nodes. Specifically, we should be able to add a tag to our Github PRs that should allow them to be tested on devices in addition to our typical simulator/emulator testing. That way we can flag only very specific PRs that we think may touch something like encryption, or may be a high impact change to do more extensive testing without necessarily having every single PR go through it.