Address Android handling of short discriminators

[bzbarsky-apple]

Problem

In #21187 I left the Android behavior around short discriminators the same as it was before: they are 0-padded to look like a long discriminator with all low bits 0. This happens in two places:

1. BLEManagerImpl::NewConnection in src/platform/android/BLEManagerImpl.cpp
2. TransformSetupPayload in src/setup_payload/java/SetupPayloadParser-JNI.cpp

Proposed Solution

What needs to happen is to figure out how short discriminators should actually be handled in the Android API and handle them accordingly.

[123yangu]

@bzbarsky-apple Do I have this problem to solve?

[bzbarsky-apple]

@123yangu I don't understand what you're asking.

[yunhanw-google]

@joonhaengHeo could you hep check whether this has been resolved. thanks

[joonhaengHeo]

I already added pairWithCode API. (#26324)
And, if using Manual Pairing Code, proceed with BLE discover with Short Discriminator.