Fix callouts test
in upstream test, it is hard code to verify path like '/-/trial_registrations/new?glm_content=gold-callout&glm_source=gitlab.com
'.
however in JH, we change the path to '/-/trial_registrations/new?glm_content=gold-callout&glm_source=jihulab
.com'.
so I extract assertion value to module, enable JH override them
JH MR, https://jihulab.com/gitlab-cn/gitlab/-/merge_requests/504
cc: @daveliu
Edited by MAO Chao