Fix backups not working when feature_flags table does not exist

See https://gitlab.com/gitlab-org/gitlab/-/merge_requests/83101

Changelog: fixed

lib/backup/manager.rb

@@ -144,7 +144,6 @@ module Backup
     def run_restore_task(task_name)
       definition = @definitions[task_name]
-      read_backup_information
       puts_time "Restoring #{definition.task.human_name} ... ".color(:blue)
       unless definition.task.enabled
@@ -483,7 +482,7 @@ module Backup
     end
     def repository_backup_strategy(incremental)
-      if Feature.enabled?(:gitaly_backup, default_enabled: :yaml)
+      if !Feature.feature_flags_available? || Feature.enabled?(:gitaly_backup, default_enabled: :yaml)
         max_concurrency = ENV['GITLAB_BACKUP_MAX_CONCURRENCY'].presence
         max_storage_concurrency = ENV['GITLAB_BACKUP_MAX_STORAGE_CONCURRENCY'].presence
         Backup::GitalyBackup.new(progress, incremental: incremental, max_parallelism: max_concurrency, storage_parallelism: max_storage_concurrency)