[processing] fixed update of MultipleInputPanel after alg is run

Fixes #20670

(cherry picked from commit e546129)

Author: volaya

python/plugins/processing/gui/MultipleInputPanel.py

@@ -83,7 +83,7 @@ def updateForOptions(self, options):
         selectedoptions = []
         selected = [self.options[i] if isinstance(i, int) else i for i in self.selectedoptions]
         for sel in selected:
-            if isinstance(sel, int):
+            if not isinstance(sel, int):
                 try:
                     idx = options.index(sel)
                     selectedoptions.append(idx)