ref(auth): Make owner optional on apiapplication (ER-1447) (#50543)

Instance level OAuth clients don't have an owner, so we need to make the
column optional.

In order to create integrated OAuth clients in
[getSentry#10782](https://github.com/getsentry/getsentry/pull/10782) we
need owners to be optional.

This work falls under a [larger
epic](https://getsentry.atlassian.net/browse/ER-1565) that, once
completed, will allow CodeCov users to seamlessly sign in with Sentry.

migrations_lockfile.txt

@@ -6,5 +6,5 @@ To resolve this, rebase against latest master and regenerate your migration. Thi
 will then be regenerated, and you should be able to merge without conflicts.
 
 nodestore: 0002_nodestore_no_dictfield
-sentry: 0479_add_timeout_at_checkin
+sentry: 0480_apiapplication_owner_optional
 social_auth: 0001_initial

src/sentry/migrations/0480_apiapplication_owner_optional.py

@@ -0,0 +1,36 @@
+# Generated by Django 2.2.28 on 2023-06-08 00:39
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations
+
+import sentry.db.models.fields.foreignkey
+from sentry.new_migrations.migrations import CheckedMigration
+
+
+class Migration(CheckedMigration):
+    # This flag is used to mark that a migration shouldn't be automatically run in production. For
+    # the most part, this should only be used for operations where it's safe to run the migration
+    # after your code has deployed. So this should not be used for most operations that alter the
+    # schema of a table.
+    # Here are some things that make sense to mark as dangerous:
+    # - Large data migrations. Typically we want these to be run manually by ops so that they can
+    #   be monitored and not block the deploy for a long period of time while they run.
+    # - Adding indexes to large tables. Since this can take a long time, we'd generally prefer to
+    #   have ops run this and not block the deploy. Note that while adding an index is a schema
+    #   change, it's completely safe to run the operation after the code has deployed.
+    is_dangerous = False
+
+    dependencies = [
+        ("sentry", "0479_add_timeout_at_checkin"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="apiapplication",
+            name="owner",
+            field=sentry.db.models.fields.foreignkey.FlexibleForeignKey(
+                null=True, on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL
+            ),
+        ),
+    ]

src/sentry/models/apiapplication.py

@@ -41,7 +41,7 @@ class ApiApplication(Model):
 
     client_id = models.CharField(max_length=64, unique=True, default=generate_token)
     client_secret = models.TextField(default=generate_token)
-    owner = FlexibleForeignKey("sentry.User")
+    owner = FlexibleForeignKey("sentry.User", null=True)
     name = models.CharField(max_length=64, blank=True, default=generate_name)
     status = BoundedPositiveIntegerField(
         default=0,