Complete the workload integration test scenarios

[ryanzhang-oss]

We have 2 pending workload integration test scenarios that need help to fill.

[ryanzhang-oss]

fleet/test/integration/cluster_placement_test.go

Line 1023 in 08e7660

XIt("Test cluster scoped resource change unpick by a placement", func() {

[Arvindthiru]

Add one more test mentioned here #337 (review)

[Arvindthiru]

#336 , #340