Fix JSX ternary nesting for textarea/input in GridTable

Remove extra curly braces around the textarea/input ternary that
caused webpack syntax error. The ternary is now a chained condition:
hasColoredWords ? <div> : text.includes('\n') ? <textarea> : <input>

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

admin-lehrer/components/grid-editor/GridTable.tsx

@@ -530,8 +530,7 @@ export function GridTable({
                             </span>
                           ))}
                         </div>
-                      ) : (
+                      ) : (cell?.text ?? '').includes('\n') ? (
-                        {(cell?.text ?? '').includes('\n') ? (
                           <textarea
                             id={`cell-${cellId}`}
                             value={cell?.text ?? ''}
@@ -576,7 +575,7 @@ export function GridTable({
                             style={{ color: cellColor || undefined }}
                             spellCheck={false}
                           />
-                        )}
+                        )
                       )}
                     </div>
                   )