Build: Remove lazy-images ES5 validation

[ockham]

yarn build-production-packages currently fails due to the recently introduced ES5 validation (#17127). (That PR probably went green in CI since it was last rebased before #17489 was merged.) This PR removes the latter, until the issues reported here are fixed.

Changes proposed in this Pull Request:

Remove ES5 validation from build-production-packages command.

Jetpack product discussion

N/A

Does this pull request change what data or activity we track or use?

No

Testing instructions:

Verify that CI goes green. Locally, verify that the following passes without errors:

`yarn build-production-packages

[matticbot]

Caution: This PR has changes that must be merged to WordPress.com
Hello ockham! These changes need to be synced to WordPress.com - If you 're an a11n, please commandeer and confirm D51563-code works as expected before merging this PR. Once this PR is merged, please commit the changes to WP.com. Thank you!
This revision will be updated with each commit to this PR

[jetpackbot]

	Warnings
⚠️	"Proposed changelog entry" is missing for this PR. Please include any meaningful changes
⚠️	pre-commit hook was skipped for one or more commits

E2E results is available here (for debugging purposes): https://jetpack-e2e-dashboard.herokuapp.com/pr-17561

This is an automated check which relies on PULL_REQUEST_TEMPLATE. We encourage you to follow that template as it helps Jetpack maintainers do their job. If you think 'Testing instructions' or 'Proposed changelog entry' are not needed for your PR - please explain why you think so. Thanks for cooperation 🤖

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[kraftbj]

FYI, no need to ask Crew for review via GH. We have a list of all 'Needs Review' PRs to review. It helps to keep our individual GH notifications clean.

[kraftbj]

Testing failures are the unrelated ones that started plaguing us yesterday seeming from something Core changed. This may need a rebase once we figure that out.

[kraftbj]

r215636-wpcom