add tests for load_csv and cypher generation, fix load csv bug

[a-s-g93]

Description

Fix bug in LoadCSVCodeGenerator class where the cypher code wasn't being properly generated Added unit tests for combined cypher generation and LoadCSVCodeGenerator

Type of Change

• [ ] New feature
• [x] Bug fix
• [ ] Breaking change
• [ ] Documentation update
• [ ] Project configuration change

Complexity

LOW

How Has This Been Tested?

• [x] Unit tests
• [ ] Integration tests
• [ ] Manual tests

Checklist

The following requirements should have been met (depending on the changes in the branch):

• [ ] Documentation has been updated if appropriate
• [x] Unit tests have been updated
• [ ] Integration tests have been updated
• [ ] Examples have been updated
• [ ] CHANGELOG.md updated if appropriate