Merge pull request #3033 from efatsi/asset-validation-fix

Add file_exists check in front of filesize lookup in Asset validation

src/fields/Assets.php

@@ -250,7 +250,7 @@ public function validateFileSize(ElementInterface $element)
                     $filenames[] = $file['filename'];
                 }
             } else {
-                if (filesize($file['location']) > $maxSize) {
+                if (file_exists($file['location']) && (filesize($file['location']) > $maxSize)) {
                     $filenames[] = $file['filename'];
                 }
             }