fix: disable sharing ui when sharing is unavailable (#22390)

Currently the sharing UI is only hidden under certain circumstances,
rather than on a permission basis. This makes it permissions based, and
makes some backend changes to make sure permissions are correct.

coderd/workspaces_test.go

@@ -5572,6 +5572,10 @@ func TestWorkspaceSharingDisabled(t *testing.T) {
 	})
 
 	t.Run("NoAccessWhenDisabled", func(t *testing.T) {
+		t.Cleanup(func() {
+			rbac.ReloadBuiltinRoles(nil)
+		})
+
 		var (
 			client, db = coderdtest.NewWithDatabase(t, &coderdtest.Options{
 				DeploymentValues: coderdtest.DeploymentValues(t, func(dv *codersdk.DeploymentValues) {