MPP-3119: add waffle_flag_by_fxa_uid command

privaterelay/management/commands/waffle_flag_by_fxa_uid.py

@@ -0,0 +1,25 @@
+from typing import Any
+
+from django.core.management.base import CommandParser
+
+from allauth.socialaccount.models import SocialAccount
+from waffle.management.commands.waffle_flag import Command as FlagCommand
+
+
+class Command(FlagCommand):
+    def add_arguments(self, parser: CommandParser) -> None:
+        parser.add_argument(
+            "--fxa",
+            action="append",
+            default=list(),
+            help="Turn on the flag for listed FXA uids.",
+        )
+        return super().add_arguments(parser)
+
+    def handle(self, *args: Any, **options: Any) -> None:
+        if "fxa" in options:
+            uids: list[str] = options.get("fxa", [])
+            for uid in uids:
+                social_account = SocialAccount.objects.get(uid=uid, provider="fxa")
+                options["user"].append(social_account.user.email)
+        return super().handle(*args, **options)