[refactor] Scan improvements (#577)

* Handle error on unexpected barcode response

* Add ManufacturerPart detail view

* Support barcode scanning for manufacturer part

* Refactoring for null checks

* Ignore selected errors in sentry

* Fix API implementation for ManufacturerPart

* Update release notes

* More error handling

* Decode quantity betterer

* Refactoring

* Add option to confirm checkin details

* Improve response handlign

* Cleanup

* Remove unused imports

* Fix async function

* Fix for assigning custom barcode

* Handle barcode scan result for company

* Fix

* Adjust scan priority

* Refactoring MODEL_TYPE

- Use instead of duplicated const strings

* @override fix

lib/widget/part/part_detail.dart

@@ -239,7 +239,7 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
 
     if (allowLabelPrinting) {
 
-      String model_type = api.supportsModernLabelPrinting ? InvenTreePart().MODEL_TYPE : "part";
+      String model_type = api.supportsModernLabelPrinting ? InvenTreePart.MODEL_TYPE : "part";
       String item_key = api.supportsModernLabelPrinting ? "items" : "part";
 
       _labels = await getLabelTemplates(