Adds MSIM config support to PhoneConfigurationManager

Some devices use the multi_sim_config property for DSDA.
For these devices, consider voice subs = 2 and statically
notify both slots as MSIM capable for the new APIs.

Bug: b/319904227
Test: atest FrameworksTelephonyTests:PhoneConfigurationManagerTest
Change-Id: I06f923cf1ced3f57d06b96dbf614aef1ea828eb1