com_finder, indexer. No visible message if finder plugins are disabled

[chmst]

Steps to reproduce the issue

Disable finder plugins, then start indexer.

You see a progressbar and a message for a few seconds, then the message disappears,.
Konsole shows a message like "no content could be indexed", but no information why.

Expected result

The indexer shows a message like "Could not index your content. Please check if the finder plugins are activated." Or something informative

Actual result

You see a progressbar and a message for one second, then the message disappears,.
Konsole shows a message like "no content could be indexed", but no information why.

System information (as much as possible)

Additional comments

[alikon]

please check #42299