Fix test validating convergent encryption behaviour across key types (#13371)

- The test was attempting to test the convergent encryption behaviour
  with several key types but the common function never used the passed
  in key type. So we ran the test with the default aes256-gcm96 only.

builtin/logical/transit/backend_test.go

@@ -989,6 +989,7 @@ func testConvergentEncryptionCommon(t *testing.T, ver int, keyType keysutil.KeyT
 		Data: map[string]interface{}{
 			"derived":               false,
 			"convergent_encryption": true,
+			"type":                  keyType.String(),
 		},
 	}
 	resp, err := b.HandleRequest(context.Background(), req)
@@ -1009,6 +1010,7 @@ func testConvergentEncryptionCommon(t *testing.T, ver int, keyType keysutil.KeyT
 		Data: map[string]interface{}{
 			"derived":               true,
 			"convergent_encryption": true,
+			"type":                  keyType.String(),
 		},
 	}
 	resp, err = b.HandleRequest(context.Background(), req)