[26761] Consistent size for notifications close icon (#6073)

Also removes global flash notices when a new success notification is
added.

https://community.openproject.com/wp/26761

[ci skip]

app/assets/javascripts/flash_messages.js

@@ -41,4 +41,4 @@ function autoHideFlashMessage() {
   setTimeout(function() {
     jQuery('.flash.autohide-notification').remove();
   }, 5000);
-}
+}

app/assets/stylesheets/content/_notifications.sass

@@ -129,7 +129,6 @@ $nm-upload-box-padding: rem-calc(15) rem-calc(25)
     width: 1rem
     height: 1rem
     text-align: center
-    font-size: 1rem
     line-height: rem-calc(20px)
     &:hover
       text-decoration: none

frontend/app/components/common/notifications/notifications.service.ts

@@ -28,6 +28,10 @@
 
 import {opServicesModule} from '../../../angular-modules';
 
+export function removeSuccessFlashMessages() {
+  jQuery('.flash.notice').remove();
+}
+
 function NotificationsService($rootScope:ng.IRootScopeService, $timeout:ng.ITimeoutService, ConfigurationService:any) {
   var createNotification = function (message:any) {
       if (typeof message === 'string') {
@@ -94,6 +98,9 @@ function NotificationsService($rootScope:ng.IRootScopeService, $timeout:ng.ITime
 
   // public
   var add = function (message:any, timeoutAfter = 5000) {
+      // Remove flash messages
+      removeSuccessFlashMessages();
+
       var notification = createNotification(message);
       broadcast('notification.add', notification);
       notificationAdded(notification);