Description of the problem:

If a user is authorized to view optimizations for a specific cluster via rbac and that cluster has optimizations available, the user will be allowed access to the optimization screen and view optimizations for that cluster (Which is expected)

If the cluster has no optimizations available and the user tries to access it, the user appears to be unauthorized when accessing the optimization plugin frontend, which is incorrect. It should allow the end user access, but state there are no optimizations available to view. 

How reproducible:

100%

Steps to reproduce:

1. Setup rbac policy file with 

    p, role:default/ROCluster, ros.cluster73, read, allow
    g, user:default/ro-read-cluster, role:default/ROCluster 

2. Login as the ro-read-cluster user

3. There should be no optimizations available for  cluster73 for this test

4.  Click on optimizations plugin ui

Actual results:

Expected results:

A message explaining to the user that there are no optimizations available for the cluster.