Fix/146 pii scrubber phone number

[a-maryam]

Summary

This PR updates the regex in pii_scrubber.py, so that phone numbers are correctly redacted. It includes associated tests

Issue

Closes #146

Changes

• Updated regex in pii_scrubber.py
• Wrote tests for redaction code

Testing

• [ X ] Unit tests pass (make test-unit): Pass
• [ X ] Integration tests pass (make test-integration): Pass
• [ X ] Linter passes (make lint): Pass
• [ X ] Type checker passes (make typecheck): Pass
• [ X ] New/updated tests cover the changes: Pass

Screenshots / Demo

Notes for Reviewers

Pre-existing linting/pre-commit hook errors in pii_scrubber.py