Bug 1817296: get rid of duplication in update verify treeherder symbols r=RyanVM,releng-reviewers,gbrown

These are pretty redundant right now, and not even consistent with what we do with other chunked things (such as tests).

Differential Revision: https://phabricator.services.mozilla.com/D170114

taskcluster/ci/release-update-verify-next/kind.yml

@@ -36,7 +36,7 @@ job-defaults:
         env:
             CHANNEL: "esr-localtest-next"
     treeherder:
-        symbol: UV(UVnext)
+        symbol: UVnext()
         kind: test
     extra:
         chunks: 12

taskcluster/ci/release-update-verify/kind.yml

@@ -32,7 +32,7 @@ job-defaults:
         retry-exit-status:
             - 255
     treeherder:
-        symbol: UV(UV)
+        symbol: UV()
         kind: test
     extra:
         chunks: 16