Log Connection.PROPERTY_CROSS_SIM to better identify xsim features

Add the "xsim" tag to Connection cross SIM property for clarity and debugging. It helps to identify xsim technologies, like xsim calling.

Bug: 397800003
Change-Id: Ib1429492a945908ab91451769d7b969a6fddeec8
Test: atest ConnectionTest
Flag: EXEMPT (debug only)