Backfill project organization_id column

Ensure all Projects are associated to an Organization

Changelog: other

db/post_migrate/20241018084652_backfill_projects_organization_id.rb

+# frozen_string_literal: true
+
+class BackfillProjectsOrganizationId < Gitlab::Database::Migration[2.2]
+  milestone '17.6'
+  restrict_gitlab_migration gitlab_schema: :gitlab_main_cell
+  disable_ddl_transaction!
+
+  def up
+    execute "UPDATE projects SET organization_id = 1 WHERE organization_id IS NULL"
+  end
+
+  def down
+    # no-op
+  end
+end