Before this commit, tour may end before emojis are loaded.
This results in following crash:
```
Trying to set result to failed (AssetsLoadingError: The loading of /web/assets/3949-d14fea7/mail.assets_emoji.min.js failed
at HTMLScriptElement.<anonymous> (http://127.0.0.1:8069/web/assets/3709-a5ab371/mail.assets_public.min.js:7008:270)) but found the future settled (<Future at 0x7fee7552a410 state=finished returned bool>)
```
This commit hides the crash in case the loading of emoji fail,
and instead show emoji picker without any emoji.
Fix runbot issue 19877
closes odoo/odoo#116845
Signed-off-by: Stockbauer Matthieu (tsm) <tsm@odoo.com>