Resolve "Custom excuse types aren't counted correctly in generate_person_list_with_class_register_statistics"

Closes #240 (closed)

aleksis/apps/alsijil/models.py

 from datetime import date
 from typing import Optional, Union
 from urllib.parse import urlparse
+from uuid import uuid4
 
 from django.db import models
 from django.db.models.constraints import CheckConstraint
 from django.db.models.query_utils import Q
 from django.urls import reverse
 from django.utils.formats import date_format
+from django.utils.text import slugify
 from django.utils.translation import gettext_lazy as _
 
 from calendarweek import CalendarWeek
@@ -66,7 +68,7 @@ class ExcuseType(ExtensibleModel):
 
     @property
     def count_label(self):
-        return f"{self.short_name}_count"
+        return f"excuse_type_{self.id}_count"
 
     class Meta:
         ordering = ["name"]
@@ -437,7 +439,7 @@ class ExtraMark(ExtensibleModel):
 
     @property
     def count_label(self):
-        return f"{self.short_name}_count"
+        return f"extra_mark_{self.id}_count"
 
     class Meta:
         ordering = ["short_name"]