test: add DescribeCluster integration test (cadence-workflow#7344)

<!-- Describe what has changed in this PR -->
**What changed?**
Integration test for DescribeCluster has been added.

<!-- Tell your future self why have you made these changes -->
**Why?**
The lack of this test caused this
#[6338](cadence-workflow#6338), and was fixed in
cadence-workflow#6350

The responses' variables depend on each run, so they cannot be asserted.
The test asserts only that the API can return the response without
errors.

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test? Checked in staging env? -->
**How did you test it?**
Run integration tests

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change to production? -->
**Potential risks**
No risks

Signed-off-by: Seva Kaloshin <[email protected]>
Signed-off-by: Mitch O'Dea <[email protected]>

Author: arzonus

host/integration_test.go

@@ -4470,3 +4470,13 @@ func (s *IntegrationSuite) sendSignal(domainName string, execution *types.Workfl
 		Identity:          identity,
 	})
 }
+
+// TestDescribeCluster tests that DescribeCluster API returns a valid response without error
+func (s *IntegrationSuite) TestDescribeCluster() {
+	ctx, cancel := createContext()
+	defer cancel()
+
+	response, err := s.AdminClient.DescribeCluster(ctx)
+	s.Require().NoError(err)
+	s.Require().NotNil(response)
+}