fix: customize namespace generator issue

[adohe]

What type of PR is this?

/kind bug

What this PR does / why we need it:

fix customize namespace generator issue

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Additional documentation e.g., design docs, usage docs, etc.:

[coveralls]

Pull Request Test Coverage Report for Build 7307529037

• 119 of 143 (83.22%) changed or added relevant lines in 11 files are covered.
• 20 unchanged lines in 6 files lost coverage.
• Overall coverage decreased (-0.09%) to 74.546%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
pkg/modules/generators/workload/job_generator.go	10	11	90.91%
pkg/modules/generators/accessories/database/database_generator.go	8	10	80.0%
pkg/modules/generators/app_configurations_generator.go	26	28	92.86%
pkg/modules/generators/workload/secret/secret_generator.go	23	27	85.19%
pkg/modules/generators/workload/network/ports_generator.go	1	7	14.29%
pkg/modules/generators/monitoring/monitoring_generator.go	2	11	18.18%

Files with Coverage Reduction	New Missed Lines	%
pkg/modules/generators/accessories/database/database_generator.go	1	85.16%
pkg/modules/generators/workload/secret/secret_generator.go	1	92.59%
pkg/modules/generators/monitoring/monitoring_generator.go	2	74.47%
pkg/modules/generators/workload/network/ports_generator.go	2	54.76%
pkg/cmd/apply/options.go	7	71.94%
pkg/cmd/destroy/options.go	7	82.13%

Totals
Change from base Build 7298373321:	-0.09%
Covered Lines:	7345
Relevant Lines:	9853

---

💛 - Coveralls

[SparkYuan]

lgtm