fdo#77268 SVG Import: fix null pointer dereference

Change-Id: I47c591f3d8b61d60f1258db3515c6805bf42304c
Reviewed-on: https://gerrit.libreoffice.org/12472
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

filter/source/svg/svgreader.cxx

@@ -1033,6 +1033,9 @@ struct AnnotatingVisitor
                               maGradientStopVector[
                                   maGradientVector.back().maStops.back()].maStopColor );
                 break;
+            case XML_TOKEN_INVALID:
+                SAL_INFO("svg", "unhandled token");
+                break;
             default:
                 SAL_INFO("svg", "unhandled token " << getTokenName(nTokenId));
                 break;