Use already-launched OMAPI service

The Java OMAPI APK was launch-on-demand, triggered by an intent.  The
new native service is launched by init and registered with
ServiceManager.  This CL modifies SEService to check with ServiceManager
before sending the intent to launch the on-demand OMAPI service.

Note that this CL does not reference the build flag, but unless the flag
is set there will be no OMAPI service registered with ServiceManager so
it will follow the pre-existing logic.

Bug: 380331467
Flag: build.RELEASE_NATIVE_OMAPI
Test: atest VtsAidlKeyMintTargetTest
Change-Id: I8f2b0a814274660868bdab509fc7ffd22090d761