Close BTA HID host connection only if it was connected

BTIF HID host tries to close the BTA HID host connection if it
determined that the connection should be closed. However it makes
determination without considering if BTA HID host was connected or not.

Test: mmm packages/modules/Bluetooth
Test: Manual | Pair with an earbud supporting both DSA 1.0 and DSA 2.0,
frequently switch between classic audio and LE audio
Flag: com.android.bluetooth.flags.close_hid_only_if_connected
Bug: 357707854
Bug: 358241286

Change-Id: I86baf524844335fb324e80115e50669bfeb8f8b7