ensure timeout error is shown on u2f timeout (#14417) (#14431)

Backport #14417

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: 6543 <6543@obermui.de>

templates/user/auth/u2f_error.tmpl

@@ -20,7 +20,7 @@
 			<div class="hide" id="u2f-error-4">
 			{{.i18n.Tr "u2f_error_4"}}
 			</div>
-			<div class="hide u2f-error-5">
+			<div class="hide u2f_error_5">
 			{{.i18n.Tr "u2f_error_5"}}
 			</div>
 		</div>