Note use of direct conneciton with --split-cluser

[dobesv]

I found that when using --split-cluster you should also use direct connections, otherwise it just only connects to the same replica and reports its metrics as if all the replicas have exactly the same metric values.

[it-percona-cla]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
2 out of 3 committers have signed the CLA.

✅ JiriCtvrtka
✅ idoqo
❌ dobesv
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[JiriCtvrtka]

@dobesv could you sign CLA? Thank you.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.82%. Comparing base (dc46ed5) to head (66c3df0).
⚠️ Report is 145 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1134      +/-   ##
==========================================
- Coverage   70.88%   64.82%   -6.07%     
==========================================
  Files          28       29       +1     
  Lines        3569     2428    -1141     
==========================================
- Hits         2530     1574     -956     
+ Misses        904      713     -191     
- Partials      135      141       +6     

Flag	Coverage Δ
agent	64.82% <ø> (-6.07%)	⬇️

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[dobesv]

I don't mind ... but when I try, I get an error:

Maybe easier if you just recreate the same trivial change in a new PR.