chore: update pdbx examples and cmpd

[shanshanying]

• fix: [BUG] polardbx cluster create ERROR 2003 (HY000): Can't connect to MySQL server on 'polardbx-joqvbv-gms:3306' (110) kubeblocks#8846

• For PDB:

1. set password length to 16
2. use vars DN_POD_FQDN_LIST instead of DN_HEADLESS_SVC_NAME
3. update dashboard

• For PDB-Cluster

1. add check on 2*clusterName length and namespace length (<18)

• For examples

1. update examples for pdb

Create cluster and open dashboard:

1. Cluster is Running

2. dashboards

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 0.00%. Comparing base (c707fc0) to head (86f48df).
Report is 1 commits behind head on main.

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #1433   +/-   ##
=====================================
  Coverage   0.00%   0.00%           
=====================================
  Files         69      69           
  Lines       6900    6900           
=====================================
  Misses      6900    6900           

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[shanshanying]

/cherry-pick release-1.0-beta

[apecloud-bot]

🤖 says: cherry pick action finished successfully 🎉!
See: https://github.com/apecloud/kubeblocks-addons/actions/runs/12923414014