Checks if the device's SIM card(s) support phone number verification.
Optional
Optional 0-based SIM slot index to query a specific slot instead of all slots.
Array of support results, one per SIM slot.
This method does not require user consent and can be called freely. Returns one VerificationSupportResult per SIM slot (or one entry if simSlot is specified).
VerificationSupportResult
simSlot
https://firebase.google.com/docs/phone-number-verification
Checks if the device's SIM card(s) support phone number verification.