Remove the Group Box Example from the repository, eliminating the
associated example codes, screenshot, and documentation file. The
only relevant portion used in the QGroupBox class has been relocated
to the existing snippet file. Additionally, all references to this
example across other files have been removed.
Fixes: QTBUG-119980
Pick-to: 6.7 6.6
Change-Id: I66f9dd9dab1fe64f2d20424af3acd135201827d2
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>
f371f8a64d