chore: Upgrade Python requirements

[edx-requirements-bot]

Python requirements update. Please review the changelogs for the upgraded packages.

[edx-requirements-bot]

List of packages in the PR without any issue.

• boto3 changes from 1.35.12 to 1.35.15
• botocore changes from 1.35.12 to 1.35.15
• build changes from 1.2.1 to 1.2.2
• edx-auth-backends changes from 4.3.0 to 4.4.0
• edx-i18n-tools changes from 1.6.2 to 1.6.3
• filelock changes from 3.15.4 to 3.16.0
• moto changes from 5.0.13 to 5.0.14
• platformdirs changes from 4.2.2 to 4.3.2
• pytest changes from 8.3.2 to 8.3.3
• tox changes from 4.18.0 to 4.18.1
• virtualenv changes from 20.26.3 to 20.26.4

[edx-requirements-bot]

These Packages need manual review..

• [MAJOR] edx-rest-api-client changes from 5.7.1 to 6.0.0
• [REMOVED] lxml (5.3.0) removed from the requirements
• [NEW] lxml-html-clean (0.2.2) added to the requirements
• [NEW] lxml[html-clean] (5.3.0) added to the requirements
• [REMOVED] slumber (0.7.1) removed from the requirements

[kdmccormick]

We are closing this pull request because Registar is deprecated. If you work with 2U and you still want to make this change, you could propose it on 2U's fork of Registar, but the contribution will not be part of the Open edX project.