Studio: misc improvements for #2264

[katinthehatsite]

Related issues

Related to 2264

Proposed Changes

This PR addressed a couple of comments from #2264 that were added after that PR was merged.

Testing Instructions

A code review should be sufficient but you can also test the full flow by:

• Pull the changes from this branch
• Start Studio
• Navigate to the Sync tab
• Make sure that you don't have any WP.com sites connected to your Studio site so that the Publish site button displays in the top right corner
• Click on the Publish site button
• Observe that you are brought to WP.com
• Complete the purchase
• Wait for the site to go Atomic
• Observe that you see a popup asking you to open Studio
• Confirm that the site you just created is connected in the Sync tab (might be a couple of seconds)

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[sejas]

Looks great Kat! Thanks for the changes. I confirm the URL generated is like:

https://wordpress.com/setup/new-hosted-site/domains?ref=studio&section=publish-site&showDomainStep=true&studioSiteId=233b4a42-94f2-4aa9-8364-a9800ef87c6e&new=My+WordPress+Website

I added the section parameter to the Publish site button, so we can start tracking that. I also changed how we append the section to use searchParams.set so it won't break the URL if by mistake we introduce an invalid character.

[katinthehatsite]

Looks good to me, thank you 👍

[github-actions]

📊 Performance Test Results

Comparing adb2595 vs trunk

site-editor

Metric	trunk	adb2595	Diff	Change
load	9915.00 ms	8878.00 ms	-1037.00 ms	🟢 -10.5%

site-startup

Metric	trunk	adb2595	Diff	Change
siteCreation	25004.00 ms	19543.00 ms	-5461.00 ms	🟢 -21.8%
siteStartup	10061.00 ms	8008.00 ms	-2053.00 ms	🟢 -20.4%

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Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change