[8.15] [8.15] [serverless] updates dashboard landing pg images (backport #5576)

[mergify]

Fixes #5507 by updating dashboards landing page screenshots to reflect the new UI

Serverless previews: UI overview
Dashboards

ESS previews: UI overview
Dashboards

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This is an automatic backport of pull request #5576 done by Mergify.

[mergify]

Cherry-pick of 095c7e1 has failed:

On branch mergify/bp/8.15/pr-5576
Your branch is up to date with 'origin/8.15'.

You are currently cherry-picking commit 095c7e19.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   docs/dashboards/images/dashboards-landing-page.png

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   docs/serverless/images/dashboards-overview/-dashboards-dashboards-landing-page.png
	deleted by us:   docs/serverless/images/es-ui-overview/-dashboards-dashboards-landing-page.png

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[github-actions]

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