[FLINK-37376] Upgrade to flink-shaded 20.0

[snuyanzin]

What is the purpose of the change

The PR bump shaded version to 20.0 and guava to 33.4.0 (sync with the one from flink-shaded)

Brief change log

poms,
CsvFormatFactoryTest.java
CsvRowDataSerDeSchemaTest.java
JsonFunctionsITCase.java
NOTICE, package names

Verifying this change

This change is already covered by existing tests, such as (please describe tests).

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

• Dependencies (does it add or upgrade a dependency): (yes)
• 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: (yes)

Documentation

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

[flinkbot]

CI report:

• 8943593 Azure: SUCCESS

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