Fix CDM UI regressions

This change addresses two regressions:
UI flashing after selecting a device of the same OEM for pairing,
and occasional failure to display the spinner in the multiple devices dialog.

Flag: EXEMPT bugfix
Test: cts
Bug: 327049496
Bug: 353187081
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:fed5619a564e9e6802340cca73d11159f710cd75)
Merged-In: Iccd74ad5d74be605cf2b88edefa5bc998dfb1461
Change-Id: Iccd74ad5d74be605cf2b88edefa5bc998dfb1461