Fix creating wxRadioBox with no items in wxUniv

Don't select the first item if there are no items at all.

See #23784.

(cherry picked from commit d282cc96579ff36f00b4c2f1c9aea3cdca9dfa64)

docs/changes.txt

@@ -322,6 +322,7 @@ wxOSX:
 wxUniv:
 
 - Fix resetting the hint in wxTextCtrl when it gets focus (Kvaz1r, #23511).
+- Fix creating wxRadioBox without any items (Kvaz1r, #23784).
 
 
 3.2.2.1: (released 2023-02-13)

src/univ/radiobox.cpp

@@ -162,8 +162,10 @@ bool wxRadioBox::Create(wxWindow *parent,
     wxSize actualSize = GetSize();
     DoMoveWindow(actualPos.x, actualPos.y, actualSize.x, actualSize.y);
 
-    // radiobox should already have selection so select at least one item
-    SetSelection(0);
+    // Select first radio button if we have any buttons at all, as the radiobox
+    // should always have some selection.
+    if ( n != 0 )
+        SetSelection(0);
 
     return true;
 }