e2e: fix flakes with environment-configs suite

[turkenh]

Description of your changes

Fixes the following flakes that we're observing with the recent PRs:

=== RUN   TestEnvironmentConfigMultipleMaxMatch1/TestEnvironmentConfigMultipleMaxMatch1/MRHasAnnotation
    feature.go:575: there were no unfiltered referred managed resources to check
--- FAIL: TestEnvironmentConfigMultipleMaxMatch1 (10.30s)
    --- FAIL: TestEnvironmentConfigMultipleMaxMatch1/TestEnvironmentConfigMultipleMaxMatch1 (10.30s)
        --- PASS: TestEnvironmentConfigMultipleMaxMatch1/TestEnvironmentConfigMultipleMaxMatch1/CreateClaim (0.51s)
        --- FAIL: TestEnvironmentConfigMultipleMaxMatch1/TestEnvironmentConfigMultipleMaxMatch1/MRHasAnnotation (0.51s)

See https://github.com/crossplane/crossplane/actions/runs/6570834969/job/17848891695?pr=4846

I have:

• Read and followed Crossplane's contribution process.
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• Added or updated unit tests.
• Added or updated e2e tests.
• Linked a PR or a docs tracking issue to document this change.
• Added backport release-x.y labels to auto-backport this PR.

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