Improves contains validation

[spacether]

Improves contains validation by refactoring the python code for it

• only validation fns should be responsible for storing the fact that a payload is valid against n schemas
• before the PR a preprocessing helper fn was storing that info which it should not have been
• with this refactoring, the contains keyword can now be deactivated via the SchemaConfiguration class

PR checklist

• Read the contribution guidelines.
• Pull Request title clearly describes the work in the pull request and Pull Request description provides details about how to validate the work. Missing information here may result in delayed response from the community.
• Run the following to build the project and update samples:

  mvn clean package ./bin/generate-samples.sh ./bin/utils/export_docs_generators.sh 

  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/python*.
  For Windows users, please run the script in Git BASH.