Properly expect all callbacks in testStackedLinkProperties.

Currently testStackedLinkProperties accounts for some of the
NetworkCallbacks that are fired, but not all of them. The test
passes because it only ever expects LinkProperties changed
callbacks (and not, e.g., lost callbacks), because it uses
waitForIdle(), and because at the end, when the callback is
unregistered, it does not call assertNoCallback().

Add the missing callback expectation and expect a LOST callback
at the end. Also add an assertNoCallback, even though it's not
strictly necessary. Remove all the waitForIdle statements, which
are no longer necessary because every assertion happens after
waiting for a callback.

Making the expectations more precise in a separate CL will help
ensure that upcoming changes to this code don't break anything,
and will make said changes easier to review.

Bug: 65674744
Test: atest FrameworksNetTests
Test: ConnectivityServiceTest#testStackedLinkProperties passes 400 times
Change-Id: I73cda0dd029a0e6546f7272beedf841ce5a4c0dc