Avoid duplicate SetContextValue call (#33564)

And fix FIXME and TODO

services/context/context.go

@@ -166,7 +166,6 @@ func Contexter() func(next http.Handler) http.Handler {
 			ctx.PageData = map[string]any{}
 			ctx.Data["PageData"] = ctx.PageData
 
-			ctx.Base.SetContextValue(WebContextKey, ctx) // FIXME: this should be removed because NewWebContext should already set it
 			ctx.Csrf = NewCSRFProtector(csrfOpts)
 
 			// get the last flash message from cookie