ensure picker source available to prevent crash

This is crashing on simulator, but presumable if it weren't available
for other reasons (permissions?) it would also crash.

// FREEBIE

Signal/src/view controllers/MessagesViewController.m

@@ -1334,30 +1334,31 @@ typedef enum : NSUInteger {
  */
 
 - (void)takePictureOrVideo {
+    if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
+        DDLogError(@"Camera ImagePicker source not available");
+        return;
+    }
+
     UIImagePickerController *picker = [[UIImagePickerController alloc] init];
-    picker.delegate                 = self;
-    picker.allowsEditing            = NO;
     picker.sourceType = UIImagePickerControllerSourceTypeCamera;
-
-    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
-        picker.mediaTypes = @[ (NSString *)kUTTypeImage, (NSString *)kUTTypeMovie ];
+    picker.mediaTypes = @[ (__bridge NSString *)kUTTypeImage, (__bridge NSString *)kUTTypeMovie ];
+    picker.allowsEditing = NO;
+    picker.delegate = self;
     [self presentViewController:picker animated:YES completion:[UIUtil modalCompletionBlock]];
 }
-}
 
 - (void)chooseFromLibrary {
+    if (![UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {
+        DDLogError(@"PhotoLibrary ImagePicker source not available");
+        return;
+    }
+
     UIImagePickerController *picker = [[UIImagePickerController alloc] init];
-    picker.delegate                 = self;
     picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
-
-    if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {
-        NSArray *photoOrVideoTypeArray = [[NSArray alloc]
-            initWithObjects:(NSString *)kUTTypeImage, (NSString *)kUTTypeMovie, (NSString *)kUTTypeVideo, nil];
-
-        picker.mediaTypes = photoOrVideoTypeArray;
+    picker.delegate = self;
+    picker.mediaTypes = @[ (__bridge NSString *)kUTTypeImage, (__bridge NSString *)kUTTypeMovie ];
     [self presentViewController:picker animated:YES completion:[UIUtil modalCompletionBlock]];
 }
-}
 
 /*
  *  Dismissing UIImagePickerController