Composer/Tests: update test dependencies

[jrfnl]

Context

• Updated test dependencies

Summary

This PR can be summarized in the following changelog entry:

• Updated test dependencies

Relevant technical choices:

This updates the minimum version of the WP Test Utils dependency.

This also allows us to remove the work-around which was in place for Mockery not handling dynamic properties on mocked objects. This was fixed in Mockery 1.6.0, which will be used when running the tests against PHP 8.2+.

Note: PHPUnit Polyfills 1.1.0 includes a new polyfill for the assertObject[Not]HasProperty() methods. The assertions which these new assertions replace are not used in this test suite, so no test changes are needed.

Test instructions

Test instructions for the acceptance test before the PR gets merged

This PR can be acceptance tested by following these steps:

• N/A If the build passes, we're good.

[coveralls]

Pull Request Test Coverage Report for Build 6408351560

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 48.608%

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Totals
Change from base Build 6408306830:	0.0%
Covered Lines:	1100
Relevant Lines:	2263

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💛 - Coveralls