[API] Expose allowed Reactions (#11735)

* [API] Expose allowed Reactions

* dont be in soutch a rush

* add TEST

* use ElementsMatch

Co-authored-by: Lauris BH <lauris@nix.lv>

routers/api/v1/swagger/misc.go

@@ -14,3 +14,10 @@ type swaggerResponseServerVersion struct {
 	// in:body
 	Body api.ServerVersion `json:"body"`
 }
+
+// StringSlice
+// swagger:response StringSlice
+type swaggerResponseStringSlice struct {
+	// in:body
+	Body []string `json:"body"`
+}