Fix disabled `SentryClientTests` test to capture message
Description
We have a disabled test here: https://github.com/getsentry/sentry-cocoa/blob/86e8170960ad82b7f1ace0523d64dde5b751b5c5/Tests/SentryTests/SentryClientTests.swift#L135-L146
This issue has gone three weeks without activity. In another week, I will close it.
But! If you comment or otherwise update it, I will reset the clock, and if you label it Status: Backlog or Status: In Progress, I will leave it alone ... forever!
"A weed is but an unloved flower." ― Ella Wheeler Wilcox 🥀
It's absolutely not reproducible locally. And while I have seen some test failures in https://github.com/getsentry/sentry-cocoa/pull/2142 for example, testCaptureMessage wasn't among them. I think we can reenable it? I'll create a PR, run the tests a few times, see what happens.
This test is not disabled, so it must be working.
Let me know otherwise.