fix: Prevent RunContext overlap between test_run tests

[rrrkharse]

Issue #, if available:
N/A

Description of changes:
During CI Health job execution, the test_run.py integ tests keep failing due to

RuntimeError: It is not allowed to use nested 'with' statements on the Run

Ex: https://github.com/aws/sagemaker-python-sdk/actions/runs/13530847522/job/37812455750

This is due to the RunContext (which is a global context to track currently "in scope" Run) not being cleared after being set in a previous test. The reason for not being cleared is still being investigated.

To prevent further test failures due to RunContext not being cleared, and to investigate where the RunContext is failing to be cleared from, a helper fixture clear_run_context is being added.

This fixture manually resets the RunContext and logs the run name and experiment name belonging to the run who's context was not previously cleared.

Testing done:

tox -e py310 -- -s -vv tests/integ/sagemaker/experiments/test_run.py::test_run_name_vs_trial_component_name_edge_cases

Merge Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your pull request.

General

• I have read the CONTRIBUTING doc
• I certify that the changes I am introducing will be backward compatible, and I have discussed concerns about this, if any, with the Python SDK team
• I used the commit message format described in CONTRIBUTING
• I have passed the region in to all S3 and STS clients that I've initialized as part of this change.
• I have updated any necessary documentation, including READMEs and API docs (if appropriate)

Tests

• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have added unit and/or integration tests as appropriate to ensure backward compatibility of the changes
• I have checked that my tests are not configured for a specific region or account (if appropriate)
• I have used unique_name_from_base to create resource names in integ tests (if appropriate)
• If adding any dependency in requirements.txt files, I have spell checked and ensured they exist in PyPi

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