Add device to to cached device manager if it's not present

Bug: 346923808
Test: atest BluetoothDeviceDetailsFragmentTest
Flag: EXEMPT minor bug fix
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:a074f274991f6a172855e0253f49b0a6dd63c758)
Merged-In: Ia4987bc7ec93cb6b54d188922b7232d83d528f2f
Change-Id: Ia4987bc7ec93cb6b54d188922b7232d83d528f2f
1 file changed