Fix runtime status type to be a string instead of a symbol

Author: Knerio

app/graphql/types/runtime_status_type.rb

@@ -4,7 +4,7 @@ module Types
   class RuntimeStatusType < BaseEnum
     description 'Represent all available types of statuses of a runtime'
 
-    value :CONNECTED, 'No problem with connection, everything works as expected', value: :connected
-    value :DISCONNECTED, 'The runtime is disconnected, cause unknown', value: :disconnected
+    value :CONNECTED, 'No problem with connection, everything works as expected', value: 'connected'
+    value :DISCONNECTED, 'The runtime is disconnected, cause unknown', value: 'disconnected'
   end
 end