Image block: Remove unused code (#71292)

Co-authored-by: Mamaduka <[email protected]>
Co-authored-by: t-hamano <[email protected]>

Author: Mamaduka

packages/block-library/src/image/edit.js

@@ -99,7 +99,6 @@ export function ImageEdit( {
 } ) {
 	const {
 		url = '',
-		alt,
 		caption,
 		id,
 		width,
@@ -127,11 +126,6 @@ export function ImageEdit( {
 
 	const isSmallContainer = placeholderWidth && placeholderWidth < 160;
 
-	const altRef = useRef();
-	useEffect( () => {
-		altRef.current = alt;
-	}, [ alt ] );
-
 	const captionRef = useRef();
 	useEffect( () => {
 		captionRef.current = caption;