[FLINK-36809][table] Support ignoreIfExists param for createTable

[gustavodemorais]

What is the purpose of the change

Support ignoreIfExists for createTable. Works exactly the same way for other resources, like createFunction. Similar to SQL's IF NOT EXISTS.

Brief change log

• Added one more signature for TableEnvironment's createTable supporting ignoreIfExists
• Added testCreateTableIfNotExistsFromDescriptor

Verifying this change

This change added tests and can be verified as follows:

• Added test that validates that running createTable, with ignoreIfExists set to true, for an existing table leads to a no op. Also checks it doing the same ignoreIfExists set to false throws an exception.

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

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

Documentation

• Does this pull request introduce a new feature? yes
• If yes, how is the feature documented? JavaDocs

[flinkbot]

CI report:

• b366d76 UNKNOWN

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[gustavodemorais]

Forgot one detail, let me open that again