[API] Only Return Json (#13511) (#13565)

Backport #13511 

Co-authored-by: zeripath <art27@cantab.net>

templates/swagger/v1_json.tmpl

@@ -2541,6 +2541,9 @@
         "responses": {
           "200": {
             "$ref": "#/responses/Branch"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
           }
         }
       },
@@ -2582,6 +2585,9 @@
           },
           "403": {
             "$ref": "#/responses/error"
+          },
+          "404": {
+            "$ref": "#/responses/notFound"
           }
         }
       }