[Cherry-pick]Fix SubnetPort allocate address for DHCP (#934)

[yanjunz97]

No description provided.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 91.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 73.86%. Comparing base (985bd95) to head (fcfd5c0).
Report is 2 commits behind head on v4.2.0.

Files with missing lines	Patch %	Lines
pkg/nsx/services/subnet/builder.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           v4.2.0     #937      +/-   ##
==========================================
+ Coverage   73.83%   73.86%   +0.02%     
==========================================
  Files         109      109              
  Lines       15252    15253       +1     
==========================================
+ Hits        11262    11266       +4     
+ Misses       3240     3238       -2     
+ Partials      750      749       -1     

Flag	Coverage Δ
unit-tests	73.86% <91.66%> (+0.02%)	⬆️

Files with missing lines	Coverage Δ
pkg/nsx/services/subnetport/builder.go	76.51% <100.00%> (ø)
pkg/nsx/util/utils.go	89.17% <100.00%> (+0.21%)	⬆️
pkg/nsx/services/subnet/builder.go	86.20% <50.00%> (+2.87%)	⬆️

[dantingl]

/e2e