fix: Fix standalone pods and deployment health check pending.

[tejal29]

fixes: #7667

After some walkthrough, i feel its safe to remove empty namespace check. I added few tests added and realizes, ConsolidateNamespaces will never add an empty namespace to the return value if no new namespace are found.

Here is the flow of how namespaces are updated in Deploy

func New() {

// first namespace is set to "". 
defaultNamespace := ""
// then preference to kubectl.CurrentContext.Namespace if set. 

// Here cfg.GetNamespace() is opt.Namespace which is set to "" by default. This method collects all 
// namespaces in the pipeline.
namespaces, err := deployutil.GetAllPodNamespaces(cfg.GetNamespace(), cfg.GetPipelines())
}

// If user has not set any namespace on CLI or in the skaffold.yaml config 
// or in kubectl.CurrentConfig, 
// namespaces = []string{""}


func (k Deployer) Deploy(...., manifests ManifestList, ...) {

// CollectNamespace never adds "" namesapce value to namespaces 
// See tests https://github.com/GoogleContainerTools/skaffold/blob/bcbdfe043c2f334f919fa2e6ae06aed4a7578486/pkg/skaffold/kubernetes/manifest/namespace_test.go#L131 
namespaces, err := manifests.CollectNamespaces()

k.trackNamespaces(namespaces)
}


func (k *Deployer) trackNamespaces(namespaces []string) {

 // Consolidate namespaces will delete "" empty namespace if namespaces is non empty.  
// So the only case when empty
// namespace value "" is set to deployer namespace is when 
// *k.namespace already has the value in New and rendered manifest don't have any new manifests.
   *k.namespaces = deployutil.ConsolidateNamespaces(*k.namespaces, namespaces)
}

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[codecov]

Codecov Report

Merging #7691 (edc8254) into main (290280e) will decrease coverage by 3.87%.
The diff coverage is 54.44%.

@@            Coverage Diff             @@
##             main    #7691      +/-   ##
==========================================
- Coverage   70.48%   66.60%   -3.88%     
==========================================
  Files         515      587      +72     
  Lines       23150    28103    +4953     
==========================================
+ Hits        16317    18719    +2402     
- Misses       5776     8029    +2253     
- Partials     1057     1355     +298     

Impacted Files	Coverage Δ
cmd/skaffold/app/cmd/credits/export.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/deploy.go	40.90% <0.00%> (-12.94%)	⬇️
cmd/skaffold/app/cmd/test.go	44.44% <0.00%> (ø)
cmd/skaffold/skaffold.go	0.00% <0.00%> (ø)
cmd/skaffold/app/cmd/inspect_tests.go	62.50% <14.28%> (-1.14%)	⬇️
cmd/skaffold/app/cmd/render.go	35.48% <18.18%> (-5.90%)	⬇️
cmd/skaffold/app/cmd/lsp.go	28.12% <28.12%> (ø)
cmd/skaffold/app/cmd/run.go	64.28% <33.33%> (-9.63%)	⬇️
cmd/skaffold/app/cmd/fix.go	55.93% <38.88%> (-20.54%)	⬇️
cmd/skaffold/app/cmd/verify.go	41.17% <41.17%> (ø)
... and 335 more

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[aaron-prindle]

LGTM!

[aaron-prindle]

nit: perhaps as a followup issues/PR we can add integration tests that can catch these cases where our standalone health checks are pending indefinitely?