Address the PK Overflow risk for the ci_build_trace_chunks - Step 3

- Remove build_id_convert_to_bigint column
- Remove trigger_cf2f9e35f002 trigger

Related to https://gitlab.com/gitlab-org/gitlab/-/issues/338069

Changelog: added

db/post_migrate/20210906100316_drop_temporary_columns_and_triggers_for_ci_build_trace_chunks.rb

+# frozen_string_literal: true
+
+class DropTemporaryColumnsAndTriggersForCiBuildTraceChunks < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+
+  TABLE = 'ci_build_trace_chunks'
+  COLUMN = 'build_id'
+
+  # rubocop:disable Migration/WithLockRetriesDisallowedMethod
+  def up
+    with_lock_retries do
+      cleanup_conversion_of_integer_to_bigint(TABLE, COLUMN)
+    end
+  end
+  # rubocop:enable Migration/WithLockRetriesDisallowedMethod
+
+  def down
+    restore_conversion_of_integer_to_bigint(TABLE, COLUMN)
+  end
+end

db/schema_migrations/20210906100316

+b7329d4ff7ee651b56cb86c7091e0d933c4f43a77125323fb6c283eedcb737c2
\ No newline at end of file

spec/migrations/20210906100316_drop_temporary_columns_and_triggers_for_ci_build_trace_chunks_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+require_migration!('drop_temporary_columns_and_triggers_for_ci_build_trace_chunks')
+
+RSpec.describe DropTemporaryColumnsAndTriggersForCiBuildTraceChunks do
+  let(:ci_build_trace_chunks_table) { table(:ci_build_trace_chunks) }
+
+  it 'correctly migrates up and down' do
+    reversible_migration do |migration|
+      migration.before -> {
+        expect(ci_build_trace_chunks_table.column_names).to include('build_id_convert_to_bigint')
+      }
+
+      migration.after -> {
+        ci_build_trace_chunks_table.reset_column_information
+        expect(ci_build_trace_chunks_table.column_names).not_to include('build_id_convert_to_bigint')
+      }
+    end
+  end
+end