feat: enhance test setup with splash screen handling and sandbox warnings

- Added `skipSandboxWarning` option to project setup functions to streamline testing.
- Implemented logic to disable the splash screen during tests by setting `automaker-splash-shown` in sessionStorage.
- Introduced a new package.json for a test project and added a test image to the fixtures for improved testing capabilities.

test/feature-backlog-test-80497-5rxs746/test-project-1767820775187/package.json

@@ -0,0 +1,4 @@
+{
+  "name": "test-project-1767820775187",
+  "version": "1.0.0"
+}