auth tests do not run without secrets

[djmitche]

  22) services/auth/test/stories_test.js (real)                                                
       "before all" hook in "services/auth/test/stories_test.js (real)":
                                                                                               
      AssertionError [ERR_ASSERTION]: no value found for secret accountId                      
      + expected - actual                                                
                                                                                               
      -false                                                                                   
      +true                   
                 
      at /home/dustin/p/taskcluster/libraries/testing/src/secrets.js:110:7
      at Array.forEach (<anonymous>)                                      
      at Secrets.get (/home/dustin/p/taskcluster/libraries/testing/src/secrets.js:109:13)
      at Context.<anonymous> (test/helper.js:70:33)                                      

Per best practices, it should be skipping when those creds don't exist, except when NO_TEST_SKIP is set.