Unify chat timestamps format (#4806)

* Unify chat timestamps format

* Handle ISO timestamps in stats.js

* Refactor timestamp parsing on server

* Switch to ISO timestamps for character/messages creation dates

* Fix type error

* Early exist in saveGroupChat if group not found

* Remove redundant fields from temp.chat export header

* Auto-fix char creation date format on edit

* Add name to fallback chat file names

* Rename parseTimestamp server side function

public/scripts/extensions/stable-diffusion/index.js

@@ -2865,7 +2865,7 @@ function getCharacterAvatarUrl() {
     if (context.groupId) {
         const groupMembers = context.groups.find(x => x.id === context.groupId)?.members;
         const lastMessageAvatar = context.chat?.filter(x => !x.is_system && !x.is_user)?.slice(-1)[0]?.original_avatar;
-        const randomMemberAvatar = Array.isArray(groupMembers) ? groupMembers[Math.floor(Math.random() * groupMembers.length)]?.avatar : null;
+        const randomMemberAvatar = Array.isArray(groupMembers) ? groupMembers[Math.floor(Math.random() * groupMembers.length)] : null;
         const avatarToUse = lastMessageAvatar || randomMemberAvatar;
         return formatCharacterAvatar(avatarToUse);
     } else {