Fix loading container on project list (#16429)

GitOrigin-RevId: 7a98cdd49132611a3334558e2a5f283fedea84cb

services/web/frontend/stylesheets/app/project-list-react.less

@@ -645,6 +645,8 @@
 
   .loading-container {
     display: flex;
+    flex-direction: column;
+    justify-content: center;
     align-items: center;
     min-height: calc(~'100vh -' @header-height);