fix: update validation logic for Docling OCR engine and language requirements

Both Docling OCR Engine and Language(s) must be provided or both left empty.

src/lib/components/admin/Settings/Documents.svelte

@@ -161,11 +161,10 @@
 			toast.error($i18n.t('Docling Server URL required.'));
 			return;
 		}
-		if (
-			RAGConfig.CONTENT_EXTRACTION_ENGINE === 'docling' &&
-			(RAGConfig.DOCLING_OCR_ENGINE !== '' || RAGConfig.DOCLING_OCR_LANG !== '')
-		) {
-			toast.error($i18n.t('Docling OCR Engine and Language(s) required.'));
+		if (RAGConfig.CONTENT_EXTRACTION_ENGINE === 'docling' &&
+			((RAGConfig.DOCLING_OCR_ENGINE === '' && RAGConfig.DOCLING_OCR_LANG !== '') ||
+			(RAGConfig.DOCLING_OCR_ENGINE !== '' && RAGConfig.DOCLING_OCR_LANG === ''))) {
+			toast.error($i18n.t('Both Docling OCR Engine and Language(s) must be provided or both left empty.'));
 			return;
 		}