Fix the Subnet creating with stale VPC issue

[wenqiq]

When creating and deleting the same Namespace and creating a Subnet in that Namespace, the creating Subnet may fail.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 69.04762% with 13 lines in your changes missing coverage. Please review.

Project coverage is 70.61%. Comparing base (ace5b09) to head (0904e44).
Report is 12 commits behind head on main.

Files with missing lines	Patch %	Lines
pkg/nsx/services/vpc/vpc.go	61.76%	11 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #825      +/-   ##
==========================================
+ Coverage   64.78%   70.61%   +5.82%     
==========================================
  Files          96       95       -1     
  Lines       15154    15094      -60     
==========================================
+ Hits         9817    10658     +841     
+ Misses       4640     3710     -930     
- Partials      697      726      +29     

Flag	Coverage Δ
unit-tests	70.61% <69.04%> (+5.82%)	⬆️

Files with missing lines	Coverage Δ
.../controllers/networkinfo/networkinfo_controller.go	66.03% <100.00%> (+0.80%)	⬆️
pkg/nsx/services/vpc/store.go	67.36% <100.00%> (ø)
pkg/nsx/services/vpc/vpc.go	54.50% <61.76%> (-0.41%)	⬇️

... and 30 files with indirect coverage changes

[zhengxiexie]

LGTM

[zhengxiexie]

LGTM

[wenyingd]

One minor comment, others LGTM

[wenyingd]

LGTM

[timdengyun]

LGTM