Only show GIF metadata warning once

Signal/src/ViewControllers/ConversationView/ConversationViewController.m

@@ -3577,7 +3577,14 @@ typedef enum : NSUInteger {
                accessibilityIdentifier:ACCESSIBILITY_IDENTIFIER_WITH_NAME(self, @"send_gif")
                                  style:UIAlertActionStyleDefault
                                handler:^(UIAlertAction *action) {
-                                   [self showGIFMetadataWarning];
+                                   NSUserDefaults *userDefaults = NSUserDefaults.standardUserDefaults;
+                                   BOOL hasSeenGIFMetadataWarning = [userDefaults boolForKey:@"hasSeenGIFMetadataWarning"];
+                                   if (!hasSeenGIFMetadataWarning) {
+                                       [self showGIFMetadataWarning];
+                                       [userDefaults setBool:YES forKey:@"hasSeenGIFMetadataWarning"];
+                                   } else {
+                                       [self showGifPicker];
+                                   }
                                }];
     UIImage *gifImage = [UIImage imageNamed:@"actionsheet_gif_black"];
     OWSAssertDebug(gifImage);

SignalServiceKit/src/Loki/Utilities/LKUserDefaults.swift

@@ -4,6 +4,7 @@ public enum LKUserDefaults {
     
     public enum Bool : Swift.String {
         case hasLaunchedOnce
+        case hasSeenGIFMetadataWarning
         case hasSeenOpenGroupSuggestionSheet
         case hasSeenPNModeSheet
         case hasViewedSeed