fix: update project unpause to not show undefined (#43820)

## I have read the
[CONTRIBUTING.md](https://github.com/supabase/supabase/blob/master/CONTRIBUTING.md)
file.

YES

## What kind of change does this PR introduce?

When un-pausing the dashboard, the project home page on platform shows
undefined rather than the default state of "URL not available"

## Ways to test

You can pause and then unpause a project to see if this works correctly

apps/studio/data/config/project-endpoint-query.ts

@@ -34,7 +34,8 @@ export const useProjectApiUrl = (
   const protocol = settings?.app_config?.protocol ?? 'https'
   const endpoint = settings?.app_config?.endpoint
 
-  const hostEndpoint = isSuccessProjectSettings ? `${protocol}://${endpoint}` : undefined
+  const hostEndpoint =
+    isSuccessProjectSettings && endpoint ? `${protocol}://${endpoint}` : undefined
   const resolvedEndpoint = isCustomDomainsActive ? customEndpoint : hostEndpoint
   const storageEndpoint = settings?.app_config?.storage_endpoint
     ? `${IS_PLATFORM ? 'https' : protocol}://${settings?.app_config?.storage_endpoint}`