[Dialogs] Fix title icon resize on orientation change

The title icon image view size is updated after each orientation transition, causing the image to get smaller after each transition.
To fix this, we're using the original size of the titleIcon image, instead of the current size of the titleImageView to determine the actual size of the image.

PiperOrigin-RevId: 319127689

components/Dialogs/src/private/MDCAlertControllerView+Private.m

@@ -594,6 +594,7 @@ - (CGFloat)accessoryVerticalInset {
   return ([self hasMessage] && [self hasAccessoryView]) ? self.accessoryViewVerticalInset : 0.0f;
 }
 
+// Returns the size of the title view or the current size of the title icon imageView.
 - (CGSize)titleIconViewSize {
   if (self.titleIconView != nil) {
     return self.titleIconView.frame.size;
@@ -603,6 +604,16 @@ - (CGSize)titleIconViewSize {
   return CGSizeZero;
 }
 
+// Returns the size of the title view or the original size of the title icon image.
+- (CGSize)titleIconImageSize {
+  if (self.titleIconView != nil) {
+    return self.titleIconView.frame.size;
+  } else if (self.titleIcon != nil) {
+    return self.titleIcon.size;
+  }
+  return CGSizeZero;
+}
+
 - (CGRect)titleFrameWithTitleSize:(CGSize)titleSize {
   CGFloat leftInset = self.titleInsets.left;
   CGFloat titleTop =
@@ -622,7 +633,7 @@ - (CGRect)messageFrameWithSize:(CGSize)messageSize {
  @param boundsSize is the total bounds without any internal margins or padding.
 */
 - (CGRect)titleIconFrameWithTitleSize:(CGSize)titleSize boundsSize:(CGSize)boundsSize {
-  CGSize titleIconViewSize = [self titleIconViewSize];
+  CGSize titleIconViewSize = [self titleIconImageSize];
   CGFloat leftInset = self.titleIconInsets.left;
   CGFloat topInset = self.titleIconInsets.top;
   CGFloat titleIconHeight = titleIconViewSize.height;