Revert verifysignature variablization in bundle (#13253)

In #13200 the dev env was changed to make `verifysignature` optional,
dependent on a variable set before ansible gets run to set up the
`docker-compose` environment.

However along with that change, a change to the execution node install
bundle slipped in, which is seemingly unrelated to the dev env change
and is breaking some installs: #13234, ansible/awx-operator#1132.

I think this change was unintentional as it would at least require
another change in ansible/receptor-collection and maybe a change in
ansible/awx-operator as well.

Signed-off-by: Rick Elrod <rick@elrod.me>

awx/api/templates/instance_install_bundle/group_vars/all.yml

@@ -7,7 +7,7 @@ receptor_work_commands:
     command: ansible-runner
     params: worker
     allowruntimeparams: true
-    verifysignature: {{ sign_work }}
+    verifysignature: true
 custom_worksign_public_keyfile: receptor/work-public-key.pem
 custom_tls_certfile: receptor/tls/receptor.crt
 custom_tls_keyfile: receptor/tls/receptor.key