chore: use pypi dependency for durable executions python SDK

[bchampp]

Which issue(s) does this change fix?

Why is this change necessary?

Rather than depending on a .whl file of the durable functions python SDK, we can depend on the actual module from pypi instead. This ensures that integration tests are being run against the latest version of the library.

How does it address the issue?

Removing the .whl file in favour of installing the actual dependency.

What side effects does this change have?

None.

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• Review the generative AI contribution guidelines
• Add input/output type hints to new functions/methods
• Write design document if needed (Do I need to write a design document?)
• Write/update unit tests
• Write/update integration tests
• Write/update functional tests if needed
• make pr passes
• make update-reproducible-reqs if dependencies were changed
• Write documentation

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.