[processing] Fix intersect always selected in Join by Location in modeler

Fixes #18489

(cherry-picked from e0255b3)

Author: nyalldawson

python/plugins/processing/gui/CheckboxesPanel.py

@@ -107,9 +107,7 @@ def value(self):
     def setValue(self, value):
         if self._multiple:
             for (v, button) in self._buttons:
-                if v in value:
-                    button.setChecked(True)
+                button.setChecked(v in value)
         else:
             for v, button in self._buttons:
-                if v == value:
-                    button.setChecked(True)
+                button.setChecked(v == value)