fix(pkgrepo/suse/install): avoid managing repo if it already exists

Use ugly `zypper lr --uri` hack to get around failure if the `base_url`
already exists under a different name:

```
      ID: salt-pkgrepo-install-saltstack-suse
Function: pkgrepo.managed
    Name: systemsmanagement_saltstack_products
  Result: False
 Comment: Failed to configure repo 'systemsmanagement_saltstack_products':
          Repository 'systemsmanagement_saltstack_products' already exists as 'systemsmanagement_saltstack'.
 Started: 09:28:39.154054
Duration: 2760.727 ms
```

Upstream code:

* https://github.com/saltstack/salt/blob/45cc49daed1618dbe89e1f012128c8dcab00b356/salt/modules/zypperpkg.py#L1262-L1265

salt/pkgrepo/suse/install.sls

@@ -2,6 +2,9 @@
 # vim: ft=sls
 {% from "salt/map.jinja" import salt_settings with context %}
 
+{#- Resorting to this ugly hack since the state doesn't handle if the `baseurl` is
+    already configured under another name, such as used by the `salt-bootstrap` #}
+{%- if not salt["cmd.run"]("zypper lr --uri | grep " ~ salt_settings.pkgrepo) %}
 salt-pkgrepo-install-saltstack-suse:
   pkgrepo.managed:
     - name: systemsmanagement_saltstack_products
@@ -11,3 +14,4 @@ salt-pkgrepo-install-saltstack-suse:
     - gpgcheck: 1
     - gpgkey: {{ salt_settings.key_url }}
     - gpgautoimport: true
+{%- endif %}