Re-enable connection controller tests

[joshheald]

Description

This PR re-enables the CardReaderConnectionControllerTests, which were previously disabled for failing in CI.

Xcode changes seem to have fixed this for us. I verified by running the suite 50 times in CI, it passed for all of them.

I took the opportunity to fix up some small issues with the related mocks – none of these made any difference to how the tests run.

Steps to reproduce

Check all tests run and pass in CI

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• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[wpmobilebot]

📲 You can test the changes from this Pull Request in WooCommerce iOS Prototype by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS Prototype
	Build Number	30450
	Version	PR #15749
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	1fd2921
	Installation URL	5qtke3ououv5g

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[iamgabrielma]

I verified by running the suite 50 times in CI, it passed for all of them.

Nice trick!