Propagate remote conference property to Dialer

[DESCRIPTION]
Create a public property to map PROPERTY_REMOTELY_HOSTED to
Dialer.  This property indicates if a conference is hosted on another
device or the local device.

Test: Added CTS coverage for new property.
Flag: com.android.server.telecom.flags.remotely_hosted_property
Bug: 430293079
Bug: 405460896
Change-Id: Ibbaa2fb9fdf29eee05cb4a143efe7949830b7652