Fix typo in test assertion message: "doesn'tmatch" → "doesn't match"

[LireEruel]

Summary

This pull request fixes a minor typo in the assertion message of test_4 in end_to_end_test_run.py.

The message previously said:

"doesn'tmatch the # of records received from the Monitoring API call"

It has been corrected to:

"doesn't match the # of records received from the Monitoring API call"

Notes

• No functional code changes were made.
• This change improves readability of test failure messages.
• No tests were affected or modified.

Let me know if you'd prefer this to be tracked via an issue first.

[LireEruel]

Hi team 👋

It's been a long-time dream of mine to contribute, even in the smallest way, to the Google Cloud Platform ecosystem. I'm very happy to have found this tiny typo while reading through the code — it may be a minor change, but it means a lot to me personally.

If you don't mind, I would be truly grateful if this PR could be accepted.
Thank you for all your amazing work 🙏