test: reduce the join/leave e2e test flakiness

[zhiying-lin]

Description of your changes

https://github.com/kubefleet-dev/kubefleet/actions/runs/15669145044/job/44137377529
10s is too short to deploy a deployment.

• [FAILED] [60.388 seconds]
Test member cluster join and leave flow Test cluster join and leave flow with CRP not deleted [It] should update CRP status to applied to all clusters again automatically after rejoining [Serial]
/home/runner/work/kubefleet/kubefleet/test/e2e/join_and_leave_test.go:236

  Timeline >>
  [FAILED] in [It] - /home/runner/work/kubefleet/kubefleet/test/e2e/join_and_leave_test.go:238 @ 06/16/25 01:13:20.05
  STEP: deleting placement crp-1 and related resources @ 06/16/25 01:13:20.05
  [FAILED] in [AfterAll] - /home/runner/work/kubefleet/kubefleet/test/e2e/utils_test.go:939 @ 06/16/25 01:14:10.436
  << Timeline

  [FAILED] Timed out after 10.001s.
Failed to update CRP status as expected
  Expected success, but got an error:
      <*errors.errorString | 0xc001057300>: 
      CRP status diff (-got, +want):   v1beta1.PlacementStatus{
        	SelectedResources:     Inverse(cmpopts.SortSlices, []v1beta1.ResourceIdentifier{{Version: "v1", Kind: "ConfigMap", Name: "test-configmap", Namespace: "application-1", ...}, {Version: "v1", Kind: "Namespace", Name: "application-1"}, {Group: "placement.kubernetes-fleet.io", Version: "v1beta1", Kind: "ClusterResourceEnvelope", Name: "test-cluster-resource-envelope", ...}, {Group: "placement.kubernetes-fleet.io", Version: "v1beta1", Kind: "ResourceEnvelope", Name: "test-resource-envelope", ...}}),
        	ObservedResourceIndex: "0",
        	PlacementStatuses: []v1beta1.ResourcePlacementStatus(Inverse(cmpopts.SortSlices, []v1beta1.ResourcePlacementStatus{
        		{ClusterName: "kind-cluster-1", ObservedResourceIndex: "0", Conditions: Inverse(cmpopts.SortSlices, []v1.Condition{{Type: "Applied", Status: "True", ObservedGeneration: 1, Reason: "AllWorkHaveBeenApplied", ...}, {Type: "Available", Status: "True", ObservedGeneration: 1, Reason: "AllWorkAreAvailable", ...}, {Type: "Overridden", Status: "True", ObservedGeneration: 1, Reason: "NoOverrideSpecified", ...}, {Type: "RolloutStarted", Status: "True", ObservedGeneration: 1, Reason: "RolloutStarted", ...}, ...})},
        		{ClusterName: "kind-cluster-2", ObservedResourceIndex: "0", Conditions: Inverse(cmpopts.SortSlices, []v1.Condition{{Type: "Applied", Status: "True", ObservedGeneration: 1, Reason: "AllWorkHaveBeenApplied", ...}, {Type: "Available", Status: "True", ObservedGeneration: 1, Reason: "AllWorkAreAvailable", ...}, {Type: "Overridden", Status: "True", ObservedGeneration: 1, Reason: "NoOverrideSpecified", ...}, {Type: "RolloutStarted", Status: "True", ObservedGeneration: 1, Reason: "RolloutStarted", ...}, ...})},
        		{
        			... // 5 identical fields
        			DriftedPlacements: nil,
        			DiffedPlacements:  nil,
        			Conditions: []v1.Condition(Inverse(cmpopts.SortSlices, []v1.Condition{
        				{
        					Type:               "Applied",
      - 					Status:             "False",
      + 					Status:             "True",
        					ObservedGeneration: 1,
        					... // 1 ignored field
      - 					Reason: "ApplyInProgress",
      + 					Reason: "AllWorkHaveBeenApplied",
        					... // 1 ignored field
        				},
      + 				{
      + 					Type:               "Available",
      + 					Status:             "True",
      + 					ObservedGeneration: 1,
      + 					Reason:             "AllWorkAreAvailable",
      + 				},

Fixes #

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[michaelawyu]

LGTM ;)