framework/configuration: fix connection_settings configuration

Connection settings were not being properly extracted from device_config
and not used. Meaning it was impossible to e.g. specify the adb device
to use for a run.

This ensures that connection settings are extracted, validated, and used
properly.

wa/framework/configuration/plugin_cache.py

@@ -152,7 +152,7 @@ class PluginCache(object):
 
     def _get_target_params(self, name):
         td = self.targets[name]
-        params = {p.name: p for p in chain(td.target_params, td.platform_params)}
+        params = {p.name: p for p in chain(td.target_params, td.platform_params, td.conn_params)}
         #params['connection_settings'] = {p.name: p for p in td.conn_params}
         return params