Remove unneeded legacy scope docker-worker:capability:privileged (#2014)

Author: petemoore

.taskcluster.yml

@@ -268,8 +268,6 @@ tasks:
                     expires: {$fromNow: '2 weeks'}
                     path: /backend.tar.zst
                     type: file
-              scopes:
-                - docker-worker:capability:privileged
               metadata:
                 name: Code Coverage Backend docker build
                 description: Build docker image with taskboot
@@ -309,8 +307,6 @@ tasks:
                     expires: {$fromNow: '2 weeks'}
                     path: /events.tar.zst
                     type: file
-              scopes:
-                - docker-worker:capability:privileged
               metadata:
                 name: Code Coverage Events docker build
                 description: Build docker image with taskboot