gd_acl_shim: Start schedule address rotation on first client registration

Set random address when privacy policy is registered.
Do not rotate address on every registration.

Bug: 171568335
Test: CtsVerifier
Test: gd/cert/run --host
Test: atest --host bluetooth_test_gd
Tag: #refactor
Change-Id: Ie8b8e8a111763dc62a0be9a38eac4b211fe50e17