fix to allow [#24009] to be fixed.

WM_operator_poll() could fail in cases WM_operator_name_call() would succeed because calling the operator would setup the context before calling poll.
this would result in python raising an invalid error or menu items being greyed out.

now python can also check with an operator context:
  bpy.ops.object.editmode_toggle.poll('INVOKE_SCREEN')

source/blender/editors/interface/interface.c

@@ -629,7 +629,7 @@ void uiEndBlock(const bContext *C, uiBlock *block)
 			if(but->context)
 				CTX_store_set((bContext*)C, but->context);
 
-			if(ot == NULL || WM_operator_poll((bContext*)C, ot)==0) {
+			if(ot == NULL || WM_operator_poll_context((bContext*)C, ot, but->opcontext)==0) {
 				but->flag |= UI_BUT_DISABLED;
 				but->lock = 1;
 			}