Add transcoding related utility functions to Kedro viz

[ankatiyar]

Description

To address deprecation warnings because we moved around TRANSCODING_SEPARATOR a few times :P

Development notes

QA notes

Checklist

• [ ] Read the contributing guidelines
• [ ] Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• [ ] Updated the documentation to reflect the code changes
• [ ] Added new entries to the RELEASE.md file
• [ ] Added tests to cover my changes