Fix regression on Docx Layout for non float elements

[cderv]

fix #7624

I believe this should be how to support non float element, based on what we do for html panelLayout.

Though a question: Should non float layout be tested with layout.float == nil or layout.is_float_reftarget == false ?

It seems we do both.

I added a test for docx floatless panel layout. Oddly we did not had one yet 🤷‍♂️

[cscheid]

Though a question: Should non float layout be tested with layout.float == nil or layout.is_float_reftarget == false ?

These should be equivalent, but I can see that I didn't use either of them consistently. We should clean up the code (the interaction between FloatRefTargets and Layouts is pretty ugly, so I think we should keep the explicit is_float_reftarget variable and just use that).

[cderv]

so I think we should keep the explicit is_float_reftarget variable and just use that).

So I used the right form here ! yeah ! 😉

[cscheid]

This looks good, thank you!. If you search globally for .float == nil in our lua files, you'll find that rendering panels outside of floatreftargets is still a very spotty area for us. So, if you're feeling industrious...