chore: fix e2e flakyness (#43739)

## Problem

Since the upgrade to NextJS 16.1.6, many e2e tests run fails with
timeout, probably when building or starting the studio

## Solution

- [x] Add dedicated steps for supabase setup and NextJS build to ease
debugging
- [x] Fix flakyness

e2e/studio/playwright.config.ts

@@ -25,8 +25,18 @@ const createWebServerConfig = () => {
     return undefined
   }
 
+  // We have dedicated job steps on CI to start Supabase and Studio
+  if (!IS_CI) {
+    return {
+      command: 'pnpm --workspace-root run e2e:setup:selfhosted',
+      port: WEB_SERVER_PORT,
+      timeout: WEB_SERVER_TIMEOUT,
+      reuseExistingServer: true,
+    }
+  }
+
   return {
-    command: 'pnpm --workspace-root run e2e:setup:selfhosted',
+    command: 'pnpm --workspace-root run e2e:setup:selfhosted:start-studio',
     port: WEB_SERVER_PORT,
     timeout: WEB_SERVER_TIMEOUT,
     reuseExistingServer: true,