[4.0] Fix table semantics

[C-Lodder]

Summary of Changes

The <caption> elements' parent must be <table>. It cannot go inside <thead>

[brianteeman]

I have tested this item ✅ successfully on 5377513

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[alikon]

I have tested this item ✅ successfully on 5377513

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_{This comment was created with the J!Tracker Application at issues.joomla.org/tracker/joomla-cms/32614.}

[alikon]

RTC

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[Quy]

Thanks.