One more type to remove

static/js/chart/base.test.ts

@@ -81,7 +81,7 @@ beforeEach(() => {
   // JSDom does not define SVGTSpanElements, and use SVGElement instead. Defines
   // a shim for getComputedTextLength where each character is 1 px wide.
   (window.SVGElement as any).prototype.getComputedTextLength =
-    function (): number {
+    function () {
       // Title elements don't contribute to width
       if (this.tagName === "title") {
         return 0;