bta::hf::client::is_connected Logging cleanup

Checking if device is connected requires contextual
expectation awareness otherwise it's log spam.

Provide logging with contextual awareness at proper level

Bug: 398277398
Test: m com.android.bt
Flag: EXEMPT, Logging cleanup

Change-Id: I7ec7602b7e02d585c467b02f28b136cd2db101a0