Remove CAPABILITY_CAN_PULL_CALL if the user is in an emergency call

When the user is in an emergency call, remove the ability for the user
to pull an external call to the device by removing
CAPABILITY_CAN_PULL_CALL.

Fixes: 153376754
Fixes: 144593522
Test: atest CtsTelecomTestCases
Merged-In: I592587cdcceaf8c6fcf844fdc2c74d7dc6989333
Change-Id: I592587cdcceaf8c6fcf844fdc2c74d7dc6989333