[FLINK-39010][transform] YAML Pipeline supports item subscription of Variant type #1939

Job	Run time
License Check	4m 19s
Common Unit Tests / test (11, generic, core)	7m 1s
Source Unit Tests / test (11, generic, mysql-source)	7m 0s
Pipeline Unit Tests / test (11, generic, doris, elasticsearch, fluss, hudi, iceberg, kafka, maxcompute, mysql-pipeline,...	7m 2s
Source Unit Tests / test (11, generic, db2, mongodb)	7m 1s
Pipeline E2E Tests (1-Parallelism) / test (11, 1.20.3, pipeline_e2e)	7m 0s
Source E2E Tests / test (11, 1.20.3, source_e2e)	7m 0s
Source Unit Tests / test (11, generic, postgres-source, oceanbase-source, tidb, vitess)	7m 0s
Pipeline E2E Tests (4-Parallelism) / test (11, 1.19.3, pipeline_e2e)	7m 3s
Pipeline E2E Tests (4-Parallelism) / test (11, 1.20.3, pipeline_e2e)	7m 3s
Source Unit Tests / test (11, generic, oracle, sqlserver)	7m 1s
Pipeline E2E Tests (1-Parallelism) / test (11, 1.19.3, pipeline_e2e)	7m 1s
Source E2E Tests / test (11, 1.19.3, source_e2e)	7m 2s
	1h 28m 33s

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