Changing per-app default request to TRACK_DEFAULT

Changing the per-app default request flows to fallback to a request of
type TRACK_DEFAULT as opposed to type REQUEST. The main benefit of this
change is that these requests will no longer be sent to the factories
which is desired.

Bug: 180452284
Bug: 176494815
Test: atest FrameworksNetTests
atest FrameworksNetIntegrationTests
atest CtsNetTestCasesLatestSdk

Change-Id: I312e55a54f70aa82953a32ab9369d5afc02b75e5
Merged-In: I312e55a54f70aa82953a32ab9369d5afc02b75e5