Steps to reproduce the issue

1. In backend, go to Components - Smart Search - Index
2. Click button Maintenance and click on "Clear Index"
3. OK on the "Are you sure ...."
4. Click button "Start the Indexer"

Expected result

A pop-up window appears to show the progress of the indexing process

Actual result

Button "Start the Indexer" doesn't work. In devtools, a JS error can be seen. Backend freezes.

System information (as much as possible)

J5 alpha 2
PHP 8.2
Mozilla firefox

Additional comments

Clicking on the "Index" button in the top bar of the window works as desired.