tiup v1.9.4 bench dose not support session settings with conn-params flag which is supported in go-tpc v1.0.8

Bug Report

tiup v1.9.4 bench dose not support session settings with conn-params flag which is supported in go-tpc v1.0.8.

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

Run TPCH with tiup bench

tiup bench tpch run -U root --db tpch --host xxxxxxxxxx.us-east-1.amazonaws.com \
--port 4000 --time 7200s --sf 100 --threads 1 --use-explain \
--conn-params="tidb_isolation_read_engines='tiflash'&tidb_allow_mpp=1&tidb_enforce_mpp=1&tidb_mem_quota_query=10737418240"  \
--password xxxxx

2. What did you expect to see?

The benchmark could be run successfully.

[centos@ip ~]$ go-tpc tpch --help
Usage:
  go-tpc tpch [command]

.......

Global Flags:
  -t, --acThreads int         OLAP client concurrency, only for CH-benCHmark (default 1)
      --conn-params string    session variables
      --count int             Total execution count, 0 means infinite
  -D, --db string             Database name (default "test")
  -d, --driver string         Database driver: mysql
      --dropdata              Cleanup data before prepare
.........

3. What did you see instead?

unknown flag: --conn-params

[centos@ip ~]$ tiup bench tpch --help
tiup is checking updates for component bench ...
Starting component `bench`: /home/centos/.tiup/components/bench/v1.9.4/tiup-bench /home/centos/.tiup/components/bench/v1.9.4/tiup-bench tpch --help
Usage:
  /home/centos/.tiup/components/bench/v1.9.4/tiup-bench tpch [command]
.......

Global Flags:
  -t, --acThreads int       OLAP client concurrency, only for CH-benCHmark (default 1)
      --count int           Total execution count, 0 means infinite
  -D, --db string           Database name (default "test")
  -d, --driver string       Database driver: mysql
      --dropdata            Cleanup data before prepare
........

4. What version of TiUP are you using (tiup --version)?

1.9.4 tiup
Go Version: go1.17.8
Git Ref: v1.9.4
GitHash: 21178655f26240da5227b64988e066586a4ea6b6

Start at the tiup bench tpch command and compare its flag handling with go-tpc v1.0.8, focusing on the missing --conn-params session-setting option. Reproduce the shown command or inspect --help, then verify that the flag is accepted and passed through when the benchmark runs.