skaffold render offline=[true|false] behaviour for namespaces is not the same

[aaron-prindle]

Currently skaffold render offline=[true|false] behaviour for namespaces is not the same. This should be the same (both of them set namespaces) but is not currently and as such can cause error/unneeded confusion for users

Related code comment:

skaffold/pkg/skaffold/render/renderer/util/util.go

Lines 66 to 67 in e258fb6

	// TODO(tejaldesai) consult with cloud deploy team if namespaces can be set in offline mode
	// in case namespace is set on the skaffold render cli command.

[aaron-prindle]

Additional context, the Cloud Deploy team specifically requested this as it is necessary functionality for skaffold render to set these namespaces regardless of offline=[true|false] for upcoming features in their roadmap