setActivity for PhoneAuthOptions in MFA Enroll (#1442)

Author: NhienLam

auth/app/src/main/java/com/google/firebase/quickstart/auth/java/MultiFactorEnrollFragment.java

@@ -110,6 +110,7 @@ public void onComplete(@NonNull Task<MultiFactorSession> task) {
                                 if (task.isSuccessful()) {
                                     PhoneAuthOptions phoneAuthOptions =
                                             PhoneAuthOptions.newBuilder()
+                                                    .setActivity(requireActivity())
                                                     .setPhoneNumber(phoneNumber)
                                                     // A timeout of 0 disables SMS-auto-retrieval.
                                                     .setTimeout(0L, TimeUnit.SECONDS)

auth/app/src/main/java/com/google/firebase/quickstart/auth/kotlin/MultiFactorEnrollFragment.kt

@@ -78,6 +78,7 @@ class MultiFactorEnrollFragment : BaseFragment() {
                 .addOnCompleteListener { task ->
                     if (task.isSuccessful) {
                         val phoneAuthOptions = PhoneAuthOptions.newBuilder()
+                                .setActivity(requireActivity())
                                 .setPhoneNumber(phoneNumber) // A timeout of 0 disables SMS-auto-retrieval.
                                 .setTimeout(0L, TimeUnit.SECONDS)
                                 .setMultiFactorSession(task.result!!)