Add expired services removal flag

The TTL check and removal of expired services is currently only
performed when a mDNS query is sent. This can result in expired
services remaining in the cache if no queries are sent. To
address this, the remaining TTL will be checked when retrieving
services from the MdnsServiceCache. Add a new flag to enable
the expired services removal feature. This feature will be
implemented in subsequent changes.

Bug: 265787401
Bug: 304649384
Test: atest FrameworksNetTests CtsNetTestCases
Change-Id: I30f0eea568ee45d363cc02821de0921d6040f981