Backport BT pairing dialog changes

This is a combination of two commits against b/409868905, merged for
backport convenience.  It updates the string and button style for the BT
pairing dialog.

Bug: 236134583
Bug: 236134775
Test: local tested
Flag: EXEMPT minor style update
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:7729bf65591b934de1efe7d9aa6520aaf87c1097
Merged-In: Icd9f509b5363b3ec3900738e21486e54d4e66e4b
Change-Id: Icd9f509b5363b3ec3900738e21486e54d4e66e4b