Revert "Merge branch 'ggillies/sidekiq-database-init-container' into 'master'"

What does this MR do?

This reverts !833 (merged)

We did not validate that the secrets mount was available to the sidekiq pods. No harm was done, let's revert such that what is on master properly represets what is currently on the staging sidekiq deployments.

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• Reviewed the diff jobs to confirm changes are as expected
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