fix: uncomment multi-az test assertion for valkey cluster

The test was failing because the Multi-AZ assertion for Valkey was commented out,
but the Valkey cluster is configured with multi_az_enabled = true and node_count = 2.
This change ensures the test properly validates Multi-AZ is enabled for both Redis 
and Valkey clusters.

Co-authored-by: Brian - oozou <lycbrian@users.noreply.github.com>

Author: claude[bot]

tests/terraform_test.go

@@ -182,6 +182,7 @@ func testElasticacheClustersCreated(t *testing.T, terraformOptions *terraform.Op
 		assert.Equal(t, "valkey", *rg.Engine, "Engine should be valkey")
 		assert.True(t, *rg.AtRestEncryptionEnabled, "At-rest encryption should be enabled")
 		assert.True(t, *rg.TransitEncryptionEnabled, "Transit encryption should be enabled")
+		assert.Equal(t, "enabled", string(rg.MultiAZ), "Multi-AZ should be enabled for Valkey cluster")
 	}
 }