Fix TestManager_FakeShipper flakiness.

[blakerouse]

What does this PR do?

Removes skip on the TestManager_FakeShipper and fixes the flakiness of the test. The issue was the test didn't wait for the shippers input and output unit to be healthy before performing the sending of the event test.

Why is it important?

Ensures that testing and configuration of a component and shipper works correctly.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works
• [ ] I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

Related issues

• Closes pkg/component/runtime.TestManager_FakeShipper test is flaky #2301

[mergify]

This pull request does not have a backport label. Could you fix it @blakerouse? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v./d./d./d is the label to automatically backport to the 8./d branch. /d is the digit

NOTE: backport-skip has been added to this pull request.

[elasticmachine]

💚 Build Succeeded

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Build stats

• Start Time: 2023-04-12T19:47:44.214+0000

• Duration: 17 min 40 sec

Test stats 🧪

Test	Results
Failed	0
Passed	5455
Skipped	19
Total	5474

💚 Flaky test report

Tests succeeded.

🤖 GitHub comments

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[elasticmachine]

🌐 Coverage report

Name	Metrics % (covered/total)	Diff
Packages	98.507% (66/67)	👍
Files	69.869% (160/229)	👍 0.437
Classes	69.108% (302/437)	👍 0.458
Methods	54.316% (925/1703)	👍 0.176
Lines	39.674% (10455/26352)	👍 0.338
Conditionals	100.0% (0/0)	💚

[ycombinator]

Left a couple of nitpicks but LGTM.