Change order custom status via api (#11982)

* Set custom_status_key via API

Refactor `custom_status_key` to be writable via the API and validate that the proposed value is valid for the current order status

* Refactor status_text serializer to consider custom status label

* Update api_version.py

* Additional unit testagainst N + 1

---------

Co-authored-by: Matthias Mair <code@mjmair.com>
Co-authored-by: Oliver Walters <oliver.henry.walters@gmail.com>

src/backend/InvenTree/order/models.py

@@ -590,6 +590,21 @@ class Order(
         """Return the Address associated with this order."""
         return self.address or self.company.primary_address
 
+    @property
+    def status_text(self):
+        """Return the text representation of the current status. This will consider any custom status."""
+        if self.get_custom_status() is not None:
+            from generic.states.custom import (
+                get_logical_value as get_custom_state_logical_value,
+            )
+
+            custom_status = get_custom_state_logical_value(
+                self.get_custom_status(), model=self._meta.model_name
+            )
+            return custom_status.label
+        else:
+            return self.status_class.label(self.get_status())
+
     @classmethod
     def get_status_class(cls):
         """Return the enumeration class which represents the 'status' field for this model."""
@@ -692,11 +707,6 @@ class PurchaseOrder(TotalPriceMixin, Order):
         help_text=_('Purchase order status'),
     )
 
-    @property
-    def status_text(self):
-        """Return the text representation of the status field."""
-        return PurchaseOrderStatus.text(self.status)
-
     supplier = models.ForeignKey(
         Company,
         on_delete=models.SET_NULL,
@@ -1443,11 +1453,6 @@ class SalesOrder(TotalPriceMixin, Order):
         help_text=_('Sales order status'),
     )
 
-    @property
-    def status_text(self) -> str:
-        """Return the text representation of the status field."""
-        return SalesOrderStatus.text(self.status)
-
     customer_reference = models.CharField(
         max_length=64,
         blank=True,