fix: prevent loss of information when returning errors

Linked to:
- https://sentry.in.nuonet.fr/share/issue/5fa72de1b01b46bc81601958a2ff5fd2/
- https://sentry.in.nuonet.fr/share/issue/5a225f6400a647c0bbf1f7ea01566e63/

internal/proxy/director/layer/rewriter/layer.go

@@ -31,7 +31,7 @@ func (l *Layer) Middleware(layer *store.Layer) proxy.Middleware {
 
 			options, err := fromStoreOptions(layer.Options)
 			if err != nil {
-				director.HandleError(ctx, w, r, http.StatusInternalServerError, errors.New("could not parse layer options"))
+				director.HandleError(ctx, w, r, http.StatusInternalServerError, errors.Wrap(err, "could not parse layer options"))
 				return
 			}