Include soft_deletable? check in with_undeleted function

[rafaelofreitas]

This MR includes the following changes:

• Include soft_deletable? check in with_undeleted function to filter only the records that have a deleted_at field.
• Add support for Ecto.SubQuery in get_schema_module function to correctly identify the schema of a subquery.
• Adds tests for the with_undeleted and soft_deletable? to ensure proper functionality.

This MR improves the ability to handle soft deletion in the application and increases the test coverage for these functions.

[Dacello]

FYI, there appears to be an issue with CI but it doesnt look like tests are actually failing

[stuartjohnpage]

Thank you! ❤️