PYTHON-5890 Remove automatic synchro for local testing

[blink1073]

PYTHON-5890

Changes in this PR

Removes the run-synchro recipe from the justfile (introduced in #2887) and its use as a pre-dependency on just test and just run-tests. When invoked this way, synchro runs on all async files unconditionally — if any of those files have linting issues or are in a partially-edited state, the run fails before tests even start. Synchro already runs automatically via the pre-commit hook on commit, scoped to only the files being staged.

Test Plan

CI passes. Locally, just test and just run-tests no longer trigger synchro.

Checklist

Checklist for Author

• Did you update the changelog (if necessary)?
• Is there test coverage?
• Is any followup work tracked in a JIRA ticket? If so, add link(s). PYTHON-5895 - Run synchro on changed async files when running tests

Checklist for Reviewer

• Does the title of the PR reference a JIRA Ticket?
• Do you fully understand the implementation? (Would you be comfortable explaining how this code works to someone else?)
• Is all relevant documentation (README or docstring) updated?

[blink1073]

Follow up ticket: PYTHON-5895 - Run synchro on changed async files when running tests

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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