BUGFIX: Position tableCreationGrid absolutely

[grebaldi]

fixes: #3308

The problem described in #3308 (table creation grid does not show up) is probably a regression through #3227 (it's hard to tell precisely though).

I decided to target 7.3 however, because the fix for #3308 fixes some other oddities as well, that must have been around forever:

Before:

Peek.2023-01-04.10-48.-.Table.before.mp4

This is what happens in 7.3-8.2:

• The removeFormat button jumps to the right when the tableCreationGrid opens
• When the tableCreationGrid is open and the Block Format select box is open as well, the options of the latter would appear detached from the select box

After:

Peek.2023-01-04.10-54.-.Table.after.mp4

Now everything stays where it belongs.

[crydotsnake]

Thanks! Works as expected