A template with type MATCH_MOBILE could have empty subscriber
IDs but it should not contain one of subscriber IDs is null.
An app might still build a template through the constructor
which is annotated with @UnsupportedAppUsage. NetworkTemplate
will throw an exception when the app trying to construct a
template with type *_WILDCARD. The constructor should be
backward compatible with old version so this change is to add
the backward compatibility to have NetworkTemplate not throw
an exception.
Bug: 267701889
Test: FrameworksNetTests
Change-Id: I23a607dae508e0c53520e2edf187cb611ed36b68
69086d6cbc