refactor: remove UUID field from ComponentVersionContent

It's wasteful to have a UUID on this join table, as we already have
a unique way to address everything in it by the unique combination
of the ComponentVersion (PublishableEntityVersion) and the
ComponentVersionContent.key (file path).

Dropping this column may cause transient errors for some sites if
someone is creating components after the column was dropped, but
before the new app code is live. UUIDs are generated on the Python
side, so Django will try to generate a UUID to put into a column
that has already been dropped on the database side.

That being said, this window of time should be small, and this
feature is not in widespread use yet. I don't think a more complex
migration is warranted.

Author: ormsbee

openedx_learning/apps/authoring/components/migrations/0004_remove_componentversioncontent_uuid.py

@@ -0,0 +1,17 @@
+# Generated by Django 4.2.23 on 2025-10-02 14:00
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('oel_components', '0003_remove_componentversioncontent_learner_downloadable'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='componentversioncontent',
+            name='uuid',
+        ),
+    ]

openedx_learning/apps/authoring/components/models.py

@@ -21,7 +21,7 @@
 
 from django.db import models
 
-from ....lib.fields import case_sensitive_char_field, immutable_uuid_field, key_field
+from ....lib.fields import case_sensitive_char_field, key_field
 from ....lib.managers import WithRelationsManager
 from ..contents.models import Content
 from ..publishing.models import LearningPackage, PublishableEntityMixin, PublishableEntityVersionMixin
@@ -240,8 +240,6 @@ class ComponentVersionContent(models.Model):
     component_version = models.ForeignKey(ComponentVersion, on_delete=models.CASCADE)
     content = models.ForeignKey(Content, on_delete=models.RESTRICT)
 
-    uuid = immutable_uuid_field()
-
     # "key" is a reserved word for MySQL, so we're temporarily using the column
     # name of "_key" to avoid breaking downstream tooling. A possible
     # alternative name for this would be "path", since it's most often used as