Webservice should not return invalid JSON even when hitting a fatal error

Hitting a fatal error in a REST request results in 200 HTTP code and Fatal error trace in HTML instead of JSON.

changed milestone to %FusionDirectory 1.4

added PJ1801-0146 plugin-webservice labels

mentioned in commit 6c11bf7b

added 30m of time spent at 2021-01-28

added To Be Tested label

closed

added Fixed label and removed To Be Tested label

added telecom sud paris label