Add `hide solved problems` to VS Code command

[twchn]

🚀 Feature Proposal

Add hide solved problems to VS Code command.

Motivation

Hiding solved problems is convenient for writing, but sometimes I need to review the problems I sovled before.

[jdneo]

@taoweicn We have a setting for your request: leetcode.hideSolved

[twchn]

Sure, I know that(even the issue was opened by me).
I just want to switch that more conveniently.

[jdneo]

@taoweicn That's not a hard request. Would you like to contribute this feature?

Just update the setting and refresh the explorer.

[twchn]

I'd love to do this in my spare time.