Refactor blueprint deeplink handling in the Add site modal

[ivan-ottinger]

Related issues

• Resolves STU-1115

Proposed Changes

The goal of this PR is to streamline the handling of blueprint deeplinks in the Add site modal and improve maintainability. We are getting rid of 34 lines of code.

• remove AddSiteContentWithDeeplinkSupport component
• move blueprint deeplink-related states to useAddSite

Testing Instructions

1. Check out the PR branch and build the app with npm install && npm start.
2. Since this PR does not add any new functionality, we can focus on finding regressions in the Add site modal. Actions you can try to perform (examples):

• Remove all your local sites and try to create new sites using different options (e.g. blank new site, from local blueprint, import from backup, pull from WPCOM, ...).
• Try the same as in the previous step, but now with at least one local site already created.
• Try to open blueprint deeplinks, e.g.:

wp-studio://add-site?blueprint=eyJtZXRhIjp7InRpdGxlIjoiVGhpcyBpcyBhIHRlc3QgYmx1ZXByaW50IiwiZGVzY3JpcHRpb24iOiJJdCBpbnN0YWxscyBBc3RyYSB0aGVtZSBhbmQgWW9hc3QgU0VPIHBsdWdpbiIsImF1dGhvciI6Iml2YW4iLCJjYXRlZ29yaWVzIjpbInJzcyIsInNvY2lhbCB3ZWIiXX0sInByZWZlcnJlZFZlcnNpb25zIjp7InBocCI6IjguMyIsIndwIjoibGF0ZXN0In0sInN0ZXBzIjpbeyJzdGVwIjoiaW5zdGFsbFRoZW1lIiwidGhlbWVEYXRhIjp7InJlc291cmNlIjoid29yZHByZXNzLm9yZy90aGVtZXMiLCJzbHVnIjoiYXN0cmEifSwib3B0aW9ucyI6eyJhY3RpdmF0ZSI6dHJ1ZX19LHsic3RlcCI6Imluc3RhbGxQbHVnaW4iLCJwbHVnaW5EYXRhIjp7InJlc291cmNlIjoid29yZHByZXNzLm9yZy9wbHVnaW5zIiwic2x1ZyI6IndvcmRwcmVzcy1zZW8ifSwib3B0aW9ucyI6eyJhY3RpdmF0ZSI6dHJ1ZX19LHsic3RlcCI6ImxvZ2luIiwidXNlcm5hbWUiOiJhZG1pbiIsInBhc3N3b3JkIjoicGFzc3dvcmQifV19 

or the ones in https://jsbin.com/levaburate/2/edit?html,css,output .

3. There should be no unexpected behavior. All sites should be created correctly.

Pre-merge Checklist

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

[github-actions]

📊 Performance Test Results

Comparing 007e9fc vs trunk

site-editor

Metric	trunk	007e9fc	Diff	Change
load	13161.00 ms	13094.00 ms	-67.00 ms	🟢 -0.5%

site-startup

Metric	trunk	007e9fc	Diff	Change
siteCreation	27198.00 ms	26492.00 ms	-706.00 ms	🟢 -2.6%
siteStartup	10062.00 ms	10068.00 ms	+6.00 ms	🔴 0.1%

---

Results are median values from multiple test runs.

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

[sejas]

Thanks for cleaning the code and removing AddSiteContentWithDeeplinkSupport, now the logic is much clearer.

I tested creating the 4 types of sites as first site and as second sites, and I didn't see any regression. The issue STU-1121 is still present, but we'll tackle that in a separate PR.

[gcsecsey]

I also tested this and found no regressions with either creating the sites or running the Blueprints via deeplinks.

Thank you for carrying out the refactor, Ivan! IMO this structure is much clearer.