Remove sync datastream methods

[nathanwoctopusdeploy]

Background

This PR removes sync Halibut methods and some additional cleanup

[sc-58528]

How to review this PR

Quality :heavy_check_mark:

Pre-requisites

• [ ] I have read How we use GitHub Issues for help deciding when and where it's appropriate to make an issue.
• [ ] I have considered informing or consulting the right people, according to the ownership map.
• [ ] I have considered appropriate testing for my change.

[shortcut-integration[bot]]

This pull request has been linked to Shortcut Story #58528: After 2023.4 - Delete Sync Halibut.