Update isPotentialEmergencyNumber() feature flag dependency

Given that  isPotentialEmergencyNumber() functionality is utilized by
both calling and messaging modules, and messaging can be enabled without calling,
the function's access control should be based on either FEATURE_TELEPHONY_CALLING or
FEATURE_TELEPHONY_MESSAGING.

Bug: 395178686
Flag: EXEMPT bug fix
Test: atest CtsTelephonyTestCases --no-bazel-mode
Change-Id: I7cd4ba3eda86f4fa277b04495419b934985fe968