fix: give correct namespace in foreignObject (#11576)

Fix #11575

src/platforms/web/util/element.js

@@ -26,7 +26,7 @@ export const isHTMLTag = makeMap(
 // contain child elements.
 export const isSVG = makeMap(
   'svg,animate,circle,clippath,cursor,defs,desc,ellipse,filter,font-face,' +
-  'foreignObject,g,glyph,image,line,marker,mask,missing-glyph,path,pattern,' +
+  'foreignobject,g,glyph,image,line,marker,mask,missing-glyph,path,pattern,' +
   'polygon,polyline,rect,switch,symbol,text,textpath,tspan,use,view',
   true
 )