[Fix][Connector-V2] Fix NPE when heartbeat.action.query is configured

[dybyte]

Purpose of this pull request

Caused by: java.lang.NullPointerException
	at io.debezium.heartbeat.HeartbeatFactory.createHeartbeat(HeartbeatFactory.java:79)
	at io.debezium.pipeline.EventDispatcher.<init>(EventDispatcher.java:127)
	at io.debezium.pipeline.EventDispatcher.<init>(EventDispatcher.java:94)
	at org.apache.seatunnel.connectors.cdc.base.relational.JdbcSourceEventDispatcher.<init>(JdbcSourceEventDispatcher.java:67)
	at org.apache.seatunnel.connectors.seatunnel.cdc.mysql.source.reader.fetch.MySqlSourceFetchTaskContext.configure(MySqlSourceFetchTaskContext.java:163)
	at org.apache.seatunnel.connectors.cdc.base.source.reader.external.IncrementalSourceScanFetcher.submitTask(IncrementalSourceScanFetcher.java:85)
	at org.apache.seatunnel.connectors.cdc.base.source.reader.IncrementalSourceSplitReader.checkSplitOrStartNext(IncrementalSourceSplitReader.java:147)
	at org.apache.seatunnel.connectors.cdc.base.source.reader.IncrementalSourceSplitReader.fetch(IncrementalSourceSplitReader.java:71)

Please refer to issue #8762 .

Does this PR introduce any user-facing change?

No.

How was this patch tested?

Added tests in:

• AbstractMysqlCDCITBase
• OracleCDCIT
• PostgresCDCIT
• SqlServerCDCIT

Check list

• If any new Jar binary package adding in your PR, please add License Notice according
  New License Guide
• If necessary, please update the documentation to describe the new feature. https://github.com/apache/seatunnel/tree/dev/docs
• If necessary, please update incompatible-changes.md to describe the incompatibility caused by this PR.
• If you are contributing the connector code, please check that the following files are updated:
  1. Update plugin-mapping.properties and add new connector information in it
  2. Update the pom file of seatunnel-dist
  3. Add ci label in label-scope-conf
  4. Add e2e testcase in seatunnel-e2e
  5. Update connector plugin_config