Remove warning from Gallery component.

Decision was made to remove the check on children since there isn’t
really a strong reason. It’s the responsibility of the caller to make
sure they pass the right attributes. Also remove the automatic
generation of the alt attribute since it doesn’t make sense in most
contexts.

https://glints.atlassian.net/browse/SS-777

Author: yjwong

src/Display/Gallery/Gallery.test.tsx

@@ -17,16 +17,16 @@ const Component = ({
     initialVisibility={initialVisibility}
     imagesDisplayed={imagesDisplayed}
   >
-    <img src="1" />
-    <img src="2" />
-    <img src="3" />
-    <img src="4" />
-    <img src="5" />
-    <img src="6" />
-    <img src="7" />
-    <img src="8" />
-    <img src="9" />
-    <img src="10" />
+    <img src="1" alt="0" />
+    <img src="2" alt="1" />
+    <img src="3" alt="2" />
+    <img src="4" alt="3" />
+    <img src="5" alt="4" />
+    <img src="6" alt="5" />
+    <img src="7" alt="6" />
+    <img src="8" alt="7" />
+    <img src="9" alt="8" />
+    <img src="10" alt="9" />
   </Gallery>
 );
 
@@ -74,14 +74,6 @@ describe('<Gallery /> rendering', () => {
     );
     expect(asFragment()).toMatchSnapshot();
   });
-
-  it('should return console error when item is invalid children', () => {
-    const error = jest.spyOn(console, 'error').mockImplementation();
-    render(<GalleryItemWithInvalidChildren />);
-
-    expect(error).toBeCalledWith('Only img components allowed as children.');
-    error.mockRestore();
-  });
 });
 
 describe('<Gallery /> open and close Slider modal', () => {

src/Display/Gallery/Gallery.tsx

@@ -35,13 +35,6 @@ const Gallery = ({
 
   const getCurrentIndex = (index: number) => setCurrentIndex(index - 1);
 
-  const hasImage = React.Children.toArray(children).some(child => {
-    return React.isValidElement(child) && child.type === 'img';
-  });
-  if (!hasImage) {
-    console.error('Only img components allowed as children.');
-  }
-
   React.useEffect(function componentDidMount() {
     if (React.Children.count(children) > imagesDisplayed)
       setImageLeft(React.Children.count(children) - imagesDisplayed);
@@ -93,9 +86,7 @@ const Gallery = ({
             (data: React.ReactElement<React.HTMLProps<'img'>>, index) => (
               <Slider.Item key={`${data.props.src}_${index}`}>
                 <GalleryImageWrapper role="banner" tabIndex={0}>
-                  {React.cloneElement(data, {
-                    alt: index.toString(10),
-                  })}
+                  {data}
                 </GalleryImageWrapper>
               </Slider.Item>
             )
@@ -117,7 +108,6 @@ const Gallery = ({
                 {React.cloneElement(data, {
                   className: index === currentIndex ? 'active' : null,
                   'data-testid': 'gallery_thumbnail',
-                  alt: index.toString(10),
                 })}
               </div>
             )