fix(RHCLOUD-48919): Fix Kessel workspace 400 error during permission loading

[aferd]

Problem

As an org admin in a v2 RBAC org, the Kessel permission checks were throwing 400 validation errors:

https://console.stage.redhat.com/api/kessel/v1beta2/checkself
400 Bad Request
{
  "code": 400,
  "reason": "VALIDATOR",
  "message": "validation error: object.resource_id: must be at least 1 characters"
}

This occurred because the KesselRbacAccessProvider was passing an empty string (id: '') as the workspace resource ID before the workspace had loaded, which violated the Kessel API's validation requirement.

Solution

Changed the placeholder workspace resource ID from empty string to a valid UUID: '00000000-0000-0000-0000-000000000000'.

When the real workspace ID loads:

1. The workspace useMemo updates (depends on defaultWorkspaceId)
2. The useSelfAccessCheck hooks detect the resource.id change
3. Permission checks automatically re-run with the correct workspace ID

Testing

Local testing:

• ✅ No more 400 errors in network tab
• ✅ Kessel permissions load correctly (canReadEvents: true)
• ✅ App RBAC state correctly computed

Stage testing needed:

• Verify "Configure Events" appears in left navigation for org admins
• Verify no console errors on page load
• Verify permissions work correctly after workspace loads

Technical Details

The useSelfAccessCheck hook from @project-kessel/react-kessel-access-check@0.5.0 watches resource.id as a dependency, so it automatically re-runs when the workspace ID changes from placeholder to real value.

Fixes RHCLOUD-48919