i18n: add missing i18n (#1077)

packages/ui-default/pages/domain_user.page.js

@@ -23,12 +23,12 @@ const page = new NamedPage('domain_user', () => {
   });
 
   async function handleClickAddUser() {
-    const res = await prompt('Add User', {
+    const res = await prompt(i18n('Add User'), {
       user: {
         type: 'userId',
         required: true,
         autofocus: true,
-        label: 'Username / UID',
+        label: i18n('Username / UID'),
         columns: 6,
       },
       role: {
@@ -41,7 +41,7 @@ const page = new NamedPage('domain_user', () => {
       ...(UiContext.canForceJoin ? {
         join: {
           type: 'checkbox',
-          label: 'Mark user as joined using admin privilege',
+          label: i18n('Mark user as joined using admin privilege'),
         },
       } : {}),
     });

packages/ui-default/pages/problem_main.page.tsx

@@ -382,7 +382,7 @@ function ProblemSelectionDisplay(props) { // eslint-disable-line
         <div className="dialog__body" style={{ height: 'calc(100% - 45px)' }}>
           <div className="row">
             <div className="columns">
-              <h1>Select Problems</h1>
+              <h1>{i18n('Select Problems')}</h1>
             </div>
           </div>
           <div className="row">