[Fix] Always fill cluster_name in databricks_cluster data source (#4197)

## Changes
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## Tests
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Author: alexott

clusters/data_cluster.go

@@ -46,6 +46,7 @@ func DataSourceCluster() common.Resource {
 		}
 		data.Id = data.ClusterInfo.ClusterId
 		data.ClusterId = data.ClusterInfo.ClusterId
+		data.Name = data.ClusterInfo.ClusterName
 
 		return nil
 	})

clusters/data_cluster_test.go

@@ -37,6 +37,7 @@ func TestClusterDataByID(t *testing.T) {
 		"cluster_info.0.node_type_id":            "i3.xlarge",
 		"cluster_info.0.autoscale.0.max_workers": 4,
 		"cluster_info.0.state":                   "RUNNING",
+		"cluster_name":                           "Shared Autoscaling",
 	})
 }
 
@@ -68,6 +69,7 @@ func TestClusterDataByName(t *testing.T) {
 		"cluster_info.0.node_type_id":            "i3.xlarge",
 		"cluster_info.0.autoscale.0.max_workers": 4,
 		"cluster_info.0.state":                   "RUNNING",
+		"cluster_id":                             "abc",
 	})
 }