DOCS-3909 Browser Test Steps and Multistep API Test Edits

[alai97]

What does this PR do?

Edits the Email Validation guide and adds a link to it in the Steps page, syncs content between Multistep API Tests and Browser Test Steps, refreshes screenshots/screencasts, and reformats a lot of content.

The Browser Test Steps page contains instructions about creating HTTP requests, which are replicated from the Multistep API Test page.

Motivation

DOCS-3909

Additional Notes

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Reviewer checklist

• [ ] Review the changed files.
• [ ] Review the URLs listed in the Preview section.
• [ ] Check images for PII
• [ ] Review any mentions of "Contact Datadog support" for internal support documentation.

[github-actions[bot]]

Preview links (active after the build_preview check completes)

New or renamed files

Modified Files

• https://docs-staging.datadoghq.com/alai97/synthetics-browser-test-steps-doc-updates/synthetics/browser_tests/actions
• https://docs-staging.datadoghq.com/alai97/synthetics-browser-test-steps-doc-updates/synthetics/guide/
• https://docs-staging.datadoghq.com/alai97/synthetics-browser-test-steps-doc-updates/synthetics/guide/email-validation
• https://docs-staging.datadoghq.com/alai97/synthetics-browser-test-steps-doc-updates/synthetics/multistep

[buraizu]

Thanks, created DOCS-3925 for tracking