Add public method to retrun whether the satellite request is for an emergency or not

Bug: 350516702
Test: atest TelephonyConnectionServiceTest
Flag: com.android.internal.telephony.flags.carrier_roaming_nb_iot_ntn
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:2b315c1881b3b2cdd20295df933c771d0c5672be)
Merged-In: I59f58e141e81de1969163b44e554c2d568f6176d
Change-Id: I59f58e141e81de1969163b44e554c2d568f6176d