They both mean the same, while using a noun in the first sentence and a verb ( or a noun ) in the second one .
"Dancing" could be a noun as well. It is a verbal noun formed by adding "ing" to the verb 'dance'
Danc(e) + ING
Danc I ng
" I can't wait to see her dancing".
means you can't wait to see her act of dancing, to see her perform the dance . The sentence uses a verb ( or a noun ) here.
" I can't wait to see her dance"
You can't wait to see the performance of dance itself. It is using the noun "dance".