Adds request as a parameter to json_success as a refactor towards
making `ignored_parameters_unsupported` functionality available
for all API endpoints.
Also, removes any data parameters that are an empty dict or
a dict with the generic success response values.
Since FIXTURE_DIR_NAME is the name of the folder that contains the view
and tests modules of the webhook and another folder called "fixtures" that
store the fixtures, it is more appropriate to call it WEBHOOK_DIR_NAME,
especially when we want to refer to the view module using this variable.
Lauryn Menard
PIG208
Anders Kaseorg
Adam Birds