fix KatalystCustomConfigTargetHandler to avoid cnc being cleared when cache no synced in restart

[luomingmeng]

What type of PR is this?

Bug fixes

What this PR does / why we need it:

cnc/kcc/kcct controller should wait KatalystCustomConfigTargetHandler cache synced to aviod unexpectly behavior when cache no synced in restart.

[codecov]

Codecov Report

Patch coverage: 80.00% and project coverage change: +0.31% 🎉

Comparison is base (268d46c) 52.86% compared to head (17e27e0) 53.17%.
Report is 11 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #265      +/-   ##
==========================================
+ Coverage   52.86%   53.17%   +0.31%     
==========================================
  Files         437      443       +6     
  Lines       42486    43043     +557     
==========================================
+ Hits        22460    22888     +428     
- Misses      17575    17665      +90     
- Partials     2451     2490      +39     

Flag	Coverage Δ
unittest	53.17% <80.00%> (+0.31%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
pkg/controller/kcc/target/target_handler.go	43.62% <75.00%> (+1.06%)	⬆️
pkg/controller/kcc/cnc.go	54.46% <100.00%> (+0.21%)	⬆️
pkg/controller/kcc/kcc.go	65.61% <100.00%> (+3.83%)	⬆️
pkg/controller/kcc/kcct.go	58.31% <100.00%> (+0.10%)	⬆️

... and 38 files with indirect coverage changes

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