[FLINK-26666][python] Add support for version comparision of pyflink and flink

[bzhaoopenstack]

This patch adds a validation when user setting the FLINK_HOME env.
If the flink version from FLINK_HOME is the same as the pyflink, we
trust the FLINK_HOME, otherwise will rewrite the FLINK_HOME env anyway.

What is the purpose of the change

improve the user experience and left a suggestion before exit.

Brief change log

• Add a func for comparing the pyflink version and flink version from FLINK_HOME env
• Don't trust FLINK_HOME if the system env had been setting before validation
• Even FLINK_HOME env had been setted before running pyflink job. Once the validation is failure, the logic will overwrite the FLINK_HOME.

Verifying this change

Exec a pyflink job, and try to make sure the pyflink version and the flink version of FLINK_HOME are different.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

• Does this pull request introduce a new feature? (no)
• If yes, how is the feature documented? (not applicable)

[flinkbot]

CI report:

• c377881 Azure: SUCCESS

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