fix: update vsphere-supervisor test to skip output from retry (follow-up)

[dilyar85]

This is a follow-up change to #321 which appears still failing the CI test.

To verify, I manually updated the test code to ensure the timing issue occurs:

--- a/builder/vsphere/supervisor/step_watch_source_test.go
+++ b/builder/vsphere/supervisor/step_watch_source_test.go
@@ -116,6 +116,8 @@ func TestWatchSource_Run(t *testing.T) {
        vmObj.Status.VmIp = testVMIP
        _ = kubeClient.Update(ctx, vmObj, opt)

+       time.Sleep(time.Second)
+
        vmServiceObj.Status.LoadBalancer.Ingress[0].IP = testIngressIP
        _ = kubeClient.Update(ctx, vmServiceObj, opt)

Running the above test against upstream/main:

$ go test -count=1 -run ^TestWatchSource_Run$ github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/supervisor
2023/11/09 10:38:35 ui: Waiting for the source VM to be powered-on and accessible...
2023/11/09 10:38:36 ui: Source VM is NOT powered-on yet, continue watching...
2023/11/09 10:38:36 ui: Source VM is powered-on, waiting for an IP to be assigned...
2023/11/09 10:38:36 ui: Successfully obtained the source VM IP: 1.2.3.4
2023/11/09 10:38:36 ui: Getting source VM ingress IP from the VMService object
2023/11/09 10:38:36 ui: VMService object's ingress IP is empty, continue checking...
2023/11/09 10:38:36 Retryable error: VMService object's ingress IP is empty, continue checking...
2023/11/09 10:38:41 ui: Successfully retrieved the source VM ingress IP: 5.6.7.8
2023/11/09 10:38:41 ui: Source VM is now ready in Supervisor cluster
--- FAIL: TestWatchSource_Run (6.00s)
    utils_test.go:61: Expected output "Successfully retrieved the source VM ingress IP: 5.6.7.8" but got "VMService object's ingress IP is empty, continue checking..."
FAIL
FAIL	github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/supervisor	6.748s
FAIL

Running the above test against this PR:

$ go test -count=1 -run ^TestWatchSource_Run$ github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/supervisor
ok  	github.com/hashicorp/packer-plugin-vsphere/builder/vsphere/supervisor	6.587s

[nywilken]

Ha I was looking at this line in the previous PR and thought do we return properly here. Good catch.

[dilyar85]

I think I just have some muscle memory that avoids recursions as much as possible :)

[nywilken]

LGTM