prefer becomeFirstResponder

Feels a little more reasonable than interecepting canBecomeFirstResponder

// FREEBIE

Signal/src/ViewControllers/ConversationView/OWSMessagesComposerTextView.m

@@ -11,12 +11,19 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (BOOL)canBecomeFirstResponder
 {
-    // Intercept to scroll to bottom when text view is tapped.
-    [self.textViewPasteDelegate textViewDidChangeSize];
-
     return YES;
 }
 
+- (BOOL)becomeFirstResponder
+{
+    BOOL becameFirstResponder = [super becomeFirstResponder];
+    if (becameFirstResponder) {
+        // Intercept to scroll to bottom when text view is tapped.
+        [self.textViewPasteDelegate textViewDidChangeSize];
+    }
+    return becameFirstResponder;
+}
+
 - (BOOL)pasteboardHasPossibleAttachment
 {
     // We don't want to load/convert images more than once so we