[release-1.6] 🌱 improve release-staging build

[cahillsf]

What this PR does / why we need it:
Backport of #10095

removes the docker-image-verify sub-make from release-staging as the PR introducing it was not backported

/area release

[k8s-ci-robot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[cahillsf]

can backport this too if we want to make it a "clean" cherry-pick: #9932 - lmk

will do the same for release-1.5 once I have feedback on the above

[cahillsf]

/area release

[chrischdi]

/hold

• 🌱 read in dockerfiles from stdin  #9990

did not get cherry-picked if I see it correctly?

[cahillsf]

/hold

• 🌱 read in dockerfiles from stdin  #9990

did not get cherry-picked if I see it correctly?

ah! That is definitely true, thank you for catching

[cahillsf]

tying together, two followup PRs to ensure the workaround is backported prior to backporting the parallelization:

• [release-1.5] 🌱 read in dockerfiles from stdin #10210
• [release-1.6] 🌱 read in dockerfiles from stdin  #10209

[killianmuldoon]

/lgtm
/approve

The dockerfile from sdtin PRs should merge this morning - feel free to unhold this one once that's through.

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 2e0ac108bae64f64f8ceed388473e095f7d15772

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: killianmuldoon

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[cahillsf]

/unhold

[cahillsf]

opened one more to back port into release-1.5 when you have a chance to take a look @killianmuldoon @chrischdi 🙇

#10227