feat(settings): remove the platform mails switch

Broadcasts go to every active user, so the settings switch and its API
call are gone. Admin broadcast texts no longer mention an opt-out.

public/i18n/en.json

@@ -143,9 +143,7 @@
     "PROFILE_TILES_HINT": "Choose what your profile shows, and where: open your profile and click \"Customize\".",
     "FAVORITE_PLATFORM": "Favorite platform",
     "FAVORITE_PLATFORM_HINT": "Selected first when you add a game on more than one platform.",
-    "FAVORITE_PLATFORM_NONE": "None",
-    "PLATFORM_MAILS": "Mails from the platform",
-    "PLATFORM_MAILS_HINT": "News and announcements by mail. Mails about your account always come."
+    "FAVORITE_PLATFORM_NONE": "None"
   },
   "VALIDATION": {
     "EMAIL_REQUIRED": "Email is required.",
@@ -718,7 +716,7 @@
     "SUBJECT_DE": "Subject (German)",
     "BODY_EN": "Text (English)",
     "BODY_DE": "Text (German)",
-    "TEXT_HELP": "Plain text, both languages. Subject max 150, text max 5000 characters. A footer with the opt-out link is added.",
+    "TEXT_HELP": "Plain text, both languages. Subject max 150, text max 5000 characters. A footer is added.",
     "RECIPIENTS": "Recipients",
     "ALL": "All active users",
     "PICKED": "Picked users",
@@ -732,7 +730,7 @@
     "CONFIRM_TEXT": "Send to {{count}} users? This cannot be undone.",
     "CONFIRM": "Send",
     "CANCEL": "Cancel",
-    "NO_RECIPIENTS": "No recipient: nobody active with mails on.",
+    "NO_RECIPIENTS": "No recipient: nobody active among them.",
     "SENT": "Mail queued for {{count}} users.",
     "ERROR": "The action failed.",
     "LIST": "Sent mails",