Update mail extension

[ViGeng]

Description

• Add preference for See Recent Mail: unreadonly to show whether only unread messages.

The motivation is that:
When I used the See Recent Mail action, I thought it had bugs since I could not see any emails from my inbox.
When I checked the extension code, I finally realized this command (action) by default only shows unread emails while there is no convenient alternative command to check inbox. (`see mail accounts needs further steps, command -> choose account -> email list).

• The most simple way is to add a preference which lets users decide what they want to show.
• There is another way of providing extra command (action) for checking inbox emails, which is to say, Check inboxes.

Screencast

Checklist

• I read the extension guidelines
• I read the documentation about publishing
• I ran npm run build and tested this distribution build in Raycast
• I checked that files in the assets folder are used by the extension itself
• I checked that assets used by the README are placed outside of the metadata folder

[raycastbot]

Thank you for your contribution! 🎉

🔔 @yug2005 @ikupenov @pernielsentikaer @fengtianze @tleo19 @Luk4h @jfkisafk @StevenRCE0 @ridemountainpig you might want to have a look.

You can use this guide to learn how to check out the Pull Request locally in order to test it.

Due to our current reduced availability, the initial review may take up to 10-15 business days 🎄

[ViGeng]

I also would ask for opinions regarding the action names. See seems wired; Check would be better, I guess?
If this works for you, please let me know, and I will fix this together in this PR.

[pernielsentikaer]

What do you think @yug2005

[neo773]

I had the exact same thought when I was trying out this extension so I uninstalled it, so I agree with OP's perspective here.