[5.2] Add missing html elements to sanitizer for finder debugging

[HLeithner]

Fix for broken pr #44342

That PR wasn't tested, sadly it was my fault that it has been merged.

This PR adds the missing HTML elements which need to be allowed for the sanitizer to not break the output.

Testing:

Run the com_finder indexer in debug mode.

After indexing an article the result should be shown in the output window.

[Quy]

I have tested this item ✅ successfully on 27674cb

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[richard67]

I have tested this item ✅ successfully on 27674cb

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[richard67]

RTC

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