add dispose to files to remove controllers when not used

Frontend/patient_manager/lib/components/inputsAndButtons/mihDropdownInput.dart

@@ -88,6 +88,12 @@ class _MIHDropdownFieldState extends State<MIHDropdownField> {
     return menueList;
   }
 
+  @override
+  void dispose() {
+    _focus.dispose();
+    super.dispose();
+  }
+
   @override
   void initState() {
     menu = buidMenueOptions(widget.dropdownOptions);