[FLINK-32292] Fix TableUtils.getRowTypeInfo when the input contains Tuple

[zhipeng93]

What is the purpose of the change

Fix TableUtils.getRowTypeInfo when the input contains Tuple.

Brief change log

• Uses ExternalTypeInfo.of(..) when the input contains Tuples.
• Adds unit test to cover the fix.

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)

Documentation

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

[lindong28]

Thanks for the PR. LGTM.