Correct media device comparison behavior

Currently, QAudioDevice and QCameraDevice will rely on several members to compare them.

Many of the members in these structs are cached, and are not updated to reflect reality when devices are disconnected and reconnected. This means that if you compare a QAudioDevice with a newer instance from QMediaDevices::audioInputs(), the comparison will fail even though they represent the same physical device.

This issue should not be closed until the behavior is corrected and documented.

As discussed in QTBUG-131674, these should only compare IDs of the devices to see if they are referring to the same physical device.