Merge branch 'sh-add-if-exists-pgdump' into 'master'

Add --if-exists to pg_dump command-line in backup creation

See merge request gitlab-org/gitlab!40792

changelogs/unreleased/sh-add-if-exists-pgdump.yml

+---
+title: Add --if-exists to pg_dump command-line in backup creation
+merge_request: 40792
+author:
+type: other

lib/backup/database.rb

@@ -27,6 +27,7 @@ module Backup
           progress.print "Dumping PostgreSQL database #{config['database']} ... "
           pg_env
           pgsql_args = ["--clean"] # Pass '--clean' to include 'DROP TABLE' statements in the DB dump.
+          pgsql_args << '--if-exists'
 
           if Gitlab.config.backup.pg_schema
             pgsql_args << '-n'