Fix some textbox imports

We still don't know why some Altiums seem to save 0s for the textbox
size when dealing with text strings and some still save values.  There
must be another flag to differentiate between text strings and text
boxes but we haven't found it yet.  But until then, we still need to
link the correct string with the textbox that we generate and suppress
the border

(cherry picked from commit 5332d44b)

Fixes #18502