Revert CLI blueprint e2e test (#3961) and Windows E2E CI disable (#4008)

[gavande1]

Related issues

• Reverts Add CLI integration test for creating a site from a custom Blueprint #3961
• Reverts Disable Studio Windows E2E CI #4008

Proposed Changes

Reverts two previously merged changes, combined into a single PR:

• Add CLI integration test for creating a site from a custom Blueprint #3961 — removes the CLI integration test for creating a site from a custom Blueprint, along with the appdata-isolation changes it made to the e2e harness.
• Disable Studio Windows E2E CI #4008 — re-enables the Windows Studio E2E Buildkite job, which had been temporarily disabled.

The unrelated STUDIO_PROCESS_MANAGER_HOME env addition introduced by #3989 is preserved in the e2e helper.

Testing Instructions

• Confirm CI passes, including the re-enabled Windows E2E job.

Pre-merge Checklist

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

[gcsecsey]

The revert LGTM, let's wait for CI to pass before merging ⌛

[wpmobilebot]

📊 Performance Test Results

Comparing 3ca63bd vs trunk

app-size

Metric	trunk	3ca63bd	Diff	Change
App Size (Mac)	1316.83 MB	1316.83 MB	+0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	3ca63bd	Diff	Change
load	1102 ms	1101 ms	1 ms	⚪ 0.0%

site-startup

Metric	trunk	3ca63bd	Diff	Change
siteCreation	6549 ms	6485 ms	64 ms	🟢 -1.0%
siteStartup	1859 ms	1865 ms	+6 ms	⚪ 0.0%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

[gcsecsey]

The failing unit test is unrelated to these changes, and seems to be flay. I retriggered the unit test job.