Ignore that users do not have access to metrics

Fixes #190

The templates appear to handle this being False, so that seems the path
of least resistance.

snikket_web/user.py

@@ -97,7 +97,10 @@ class ImportAccountDataForm(BaseForm):
 @client.require_session()
 async def index() -> str:
     user_info = await client.get_user_info()
-    metrics = await client.get_system_metrics()
+    try:
+        metrics = await client.get_system_metrics()
+    except:
+        metrics = False
     return await render_template(
         "user_home.html",
         user_info=user_info,