migration(issue-views): Make groupsearchview.position nullable (#87258)

This PR makes the groupsearchview.position column nullable. This is the
first step to deleting the column entirely, since it's being superseded
by the groupsearchviewstarred.position column.

 The next steps after merging this are: 

1. Delete all usages of this column — Besides tests, there are already
no more places where we are filtering based on the position, but we need
to remove the position from any newly created entries.
2. Add migration to safe delete the column w/ pending
deletion_action=DeletionAction.MOVE_TO_PENDING
3. Add migration to fully delete the column 

^ If these steps are incorrect, please let me know. The migration docs
seem to be a little unclear about this.

Author: MichaelSun48

migrations_lockfile.txt

@@ -17,7 +17,7 @@ remote_subscriptions: 0003_drop_remote_subscription
 
 replays: 0004_index_together
 
-sentry: 0842_create_organization_member_invite_table
+sentry: 0843_make_groupsearchview_postition_nullable_for_deletion
 
 social_auth: 0002_default_auto_field
 

src/sentry/migrations/0843_make_groupsearchview_postition_nullable_for_deletion.py

@@ -0,0 +1,33 @@
+# Generated by Django 5.1.7 on 2025-03-17 22:56
+
+from django.db import migrations, models
+
+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.
+    # 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 post deployment:
+    # - Large data migrations. Typically we want these to be run manually 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
+    #   run this outside deployments so that we don't block them. Note that while adding an index
+    #   is a schema change, it's completely safe to run the operation after the code has deployed.
+    # Once deployed, run these manually via: https://develop.sentry.dev/database-migrations/#migration-deployment
+
+    is_post_deployment = False
+
+    dependencies = [
+        ("sentry", "0842_create_organization_member_invite_table"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="groupsearchview",
+            name="position",
+            field=models.PositiveSmallIntegerField(null=True),
+        ),
+    ]

src/sentry/models/groupsearchview.py

@@ -62,7 +62,7 @@ class GroupSearchView(DefaultFieldsModelExisting):
     query_sort = models.CharField(
         max_length=16, default=SortOptions.DATE, choices=SortOptions.as_choices()
     )
-    position = models.PositiveSmallIntegerField()
+    position = models.PositiveSmallIntegerField(null=True)
 
     # Projects = [] maps to "My Projects" (This is so when a project is deleted, it correctly defaults to "My Projects")
     projects = models.ManyToManyField("sentry.Project", through="sentry.GroupSearchViewProject")