Fix flexbox issue

www/common/common-ui-elements.js

@@ -418,7 +418,7 @@ define([
         var localStore = window.cryptpadStore;
         localStore.get('hide-alert-teamInvite', function (val) {
             if (val === '1') { return; }
-            $(linkWarning).show();
+            $(linkWarning).css('display', 'flex');
 
             $(dismissButton).on('click', function () {
                 localStore.put('hide-alert-teamInvite', '1');

www/common/inner/share.js

@@ -341,7 +341,7 @@ define([
 
         localStore.get('hide-alert-shareLinkWarning', function (val) {
             if (val === '1') { return; }
-            $(shareLinkWarning).show();
+            $(shareLinkWarning).css('display', 'flex');
 
             $(dismissButton).on('click', function () {
                 localStore.put('hide-alert-shareLinkWarning', '1');
@@ -737,7 +737,7 @@ define([
 
         localStore.get('hide-alert-shareLinkWarning', function (val) {
             if (val === '1') { return; }
-            $(shareLinkWarning).show();
+            $(shareLinkWarning).css('display', 'flex');
 
             $(dismissButton).on('click', function () {
                 localStore.put('hide-alert-shareLinkWarning', '1');