Add OK into queue after sendAndroidAt

Add OK into queue after sending AT command and add unit test for it.

Bug: 270294700
Test: atest GoogleBluetoothInstrumentationTests
Tag: #feature
(cherry picked from https://android-review.googlesource.com/q/commit:b68482f39cea80e9410e8a324d8ddd29379f1f2e)
Merged-In: Iff0e846f0dfe4d8fb2349e7ac9e6118b24f95706
Change-Id: Iff0e846f0dfe4d8fb2349e7ac9e6118b24f95706
Bug: 263323082