[Bluetooth Diagnosis] Change the BannerPreference to contain 2 specific buttons instead of a button list

Test: com.android.settingslib.bluetooth.BannerPreferenceTest
Bug: 411309851
Flag: com.android.settingslib.flags.enable_bluetooth_diagnosis
Change-Id: If443188a9e1680599a63c074a12c4bcbcf346719
2 files changed