[production] Disable package validation in runtime

[mtojek]

Issue: elastic/package-registry#653

This PR disables package validation in runtime as it has already been performed in the build stage.

[ruflin]

LGTM. Can you make sure to first roll out snapshot and staging to make sure they work as expected? I don't see a reason they shouldn't but just to be sure.

[mtojek]

I have already done it on snapshot (this way I measured the new boot up time :)

[elasticmachine]

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• Build Cause: Pull request #758 opened

• Start Time: 2021-01-07T09:39:50.796+0000

• Duration: 14 min 1 sec

Test stats 🧪

Test	Results
Failed	0
Passed	51
Skipped	0
Total	51