Migrate push_event_payloads.event_id back to integer (GitLab.com only)

Revert `push_event_payloads` back to using `integer` column for
`event_id`, with a migration running only on Gitlab.com.

Also make the existing migration 20210622041846 run on GitLab.com only.

https://gitlab.com/gitlab-org/gitlab/-/issues/335002

Changelog: other

db/post_migrate/20210630025020_migrate_push_event_payloads_event_id_back_to_integer_for_gitlab_com.rb

+# frozen_string_literal: true
+
+require Rails.root.join('db', 'post_migrate', '20210622041846_finalize_push_event_payloads_bigint_conversion')
+
+class MigratePushEventPayloadsEventIdBackToIntegerForGitlabCom < ActiveRecord::Migration[6.1]
+  disable_ddl_transaction!
+
+  def up
+    FinalizePushEventPayloadsBigintConversion.new.down
+  end
+
+  def down
+    FinalizePushEventPayloadsBigintConversion.new.up
+  end
+end

db/schema_migrations/20210630025020

+71ad8c8f2419721f8fdf6c6bbd1265c4a7ca277972c59319e155bc6dfc46aa48
\ No newline at end of file

db/structure.sql

@@ -17365,7 +17365,7 @@ ALTER SEQUENCE protected_tags_id_seq OWNED BY protected_tags.id;
 
 CREATE TABLE push_event_payloads (
     commit_count bigint NOT NULL,
-    event_id_convert_to_bigint integer DEFAULT 0 NOT NULL,
+    event_id integer NOT NULL,
     action smallint NOT NULL,
     ref_type smallint NOT NULL,
     commit_from bytea,
@@ -17373,7 +17373,7 @@ CREATE TABLE push_event_payloads (
     ref text,
     commit_title character varying(70),
     ref_count integer,
-    event_id bigint NOT NULL
+    event_id_convert_to_bigint bigint DEFAULT 0 NOT NULL
 );
 
 CREATE TABLE push_rules (