Fix toArray method in Doc class

- remove dead variables
- fix check for mime type

Classes/Common/Doc.php

@@ -1366,9 +1366,6 @@ public function toArray($uriBuilder, array $config = [])
                 'minPage' => $minPage
             ]
         ];
-        $extConf = GeneralUtility::makeInstance(ExtensionConfiguration::class)->get(self::$extKey);
-        $fileGrpsImages = array_reverse(GeneralUtility::trimExplode(',', $extConf['fileGrpImages']));
-        $fileGrpsFulltext = GeneralUtility::trimExplode(',', $extConf['fileGrpFulltext']);
 
         $allFiles = $this->getAllFiles();
 
@@ -1392,8 +1389,8 @@ public function toArray($uriBuilder, array $config = [])
                 }
 
                 // Only deliver static images via the internal PageViewProxy.
-                // (For IIP and IIIF, the viewer needs to build and access a separate metadata URL, see `getMetdadataURL`.)
-                if (in_array($fileGrp, $proxyFileGroups) && !in_array($mimetype, self::$nonProxyMimeTypes)) {
+                // (For IIP and IIIF, the viewer needs to build and access a separate metadata URL, see `getMetadataURL`.)
+                if (in_array($fileGrp, $proxyFileGroups) && !in_array($file['mimetype'], self::$nonProxyMimeTypes)) {
                     // Configure @action URL for form.
                     $file['url'] = $uriBuilder
                         ->reset()