[Issue 11558][Python] Check if the record is not None

[HugoPelletier]

Fixes #11558

Motivation

Not all sub-records are required in a schema. Taking this context into account, the code of the Record class ignored its own default values (required=False and default=None)

Modifications

The modification is a continuation of the ones made in the PR #11508.
This time only the Record class has changed. The modification affects the validation. A check of the value and the required attribute is done before validating the data type.

So if the value is empty and the required is False, the default is returned instead of raising an exception.

Verifying this change

• Make sure that the change passes the CI checks.

This change added tests and can be verified as follows:

• *Added unit tests

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

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): no
• The public API: no
• The schema: yes
• The default values of configurations: no
• The wire protocol: no
• The rest endpoints: no
• The admin cli options: no
• Anything that affects deployment: no

Documentation

For contributor

No documentation update is required.
The definition of the Record class wasn't respected

For committer

For this PR, do we need to update docs?

No