[Glitch] Disable list title validation button when list title is empty

Port 089c641020 to glitch-soc

Signed-off-by: Thibaut Girka <thib@sitedethib.com>

app/javascript/flavours/glitch/features/lists/components/new_list_form.js

@@ -66,7 +66,7 @@ export default class NewListForm extends React.PureComponent {
         </label>
 
         <IconButton
-          disabled={disabled}
+          disabled={disabled || !value}
           icon='plus'
           title={title}
           onClick={this.handleClick}