ci: fix flaky test cases since minitest 6

[supercaracal]

Our scaling test cases depend on their execution order. Minitest 6 has renamed the related method.

https://github.com/minitest/minitest/blob/master/History.rdoc

Renamed Minitest::Runnable#test_order to #run_order.

Redis:

  1) Error:
TestAgainstClusterScale::Pipeline#test_02_scale_in:
RedisClient::CommandError: ERR I don't know about node 78beed864ac1d67ae52ca3dc9fa82b39609d2686 (redis://127.0.0.1:6385)
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client/connection_mixin.rb:43:in 'RedisClient::ConnectionMixin#call'
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client.rb:369:in 'block (2 levels) in RedisClient#call_once'
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client/middlewares.rb:16:in 'RedisClient::BasicMiddleware#call'
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client.rb:368:in 'block in RedisClient#call_once'
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client.rb:788:in 'RedisClient#ensure_connected'
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client.rb:367:in 'RedisClient#call_once'
    test/cluster_controller.rb:121:in 'ClusterController#start_resharding'
    test/cluster_controller.rb:208:in 'block in ClusterController#scale_in'
    test/cluster_controller.rb:204:in 'Array#each'
    test/cluster_controller.rb:204:in 'ClusterController#scale_in'
    test/test_against_cluster_scale.rb:72:in 'TestAgainstClusterScale::Mixin#test_02_scale_in'

Valkey:

  1) Error:
TestAgainstClusterScale::Pipeline#test_02_scale_in:
RedisClient::CommandError: ERR Unknown node 203b77b3da0382c36ffe23963eb9ae2613ad5cc3 (redis://127.0.0.1:6385)
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client/connection_mixin.rb:43:in 'RedisClient::ConnectionMixin#call'
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client.rb:369:in 'block (2 levels) in RedisClient#call_once'
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client/middlewares.rb:16:in 'RedisClient::BasicMiddleware#call'
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client.rb:368:in 'block in RedisClient#call_once'
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client.rb:788:in 'RedisClient#ensure_connected'
    vendor/bundle/ruby/3.4.0/gems/redis-client-0.26.2/lib/redis_client.rb:367:in 'RedisClient#call_once'
    test/cluster_controller.rb:155:in 'block in ClusterController#finish_resharding'
    test/cluster_controller.rb:154:in 'Array#each'
    test/cluster_controller.rb:154:in 'ClusterController#finish_resharding'
    test/cluster_controller.rb:209:in 'block in ClusterController#scale_in'
    test/cluster_controller.rb:204:in 'Array#each'
    test/cluster_controller.rb:204:in 'ClusterController#scale_in'
    test/test_against_cluster_scale.rb:72:in 'TestAgainstClusterScale::Mixin#test_02_scale_in'