Fix: WebGPUTextureUtils._getDefaultCubeTextureGPU using wrong cache (#32425)

Co-authored-by: “SE7EN2028” <“RITIKGOTBUSY@GMAIL.COM”>

src/renderers/webgpu/utils/WebGPUTextureUtils.js

@@ -683,7 +683,7 @@ class WebGPUTextureUtils {
 	 */
 	_getDefaultCubeTextureGPU( format ) {
 
-		let defaultCubeTexture = this.defaultTexture[ format ];
+		let defaultCubeTexture = this.defaultCubeTexture[ format ];
 
 		if ( defaultCubeTexture === undefined ) {