Bug #119689 SSH Tunnels do not support usernames which include "@"

Description:
SSH Tunnels do not support connecting with a username that includes a "@".

How to repeat:
- Install "MySQL Shell for VS Code" extension
- Create a new DB connection
- Check box "Connect using SSH Tunnel" - this will reveal a tab "SSH Tunnel"
- Click tab "SSH Tunnel"
- Under field "SSH URI" enter a SSH URI with a username that includes "@", such as "first.last@acme.com@myserver.com"
- Try to open shell with this connection

Expected behaviour: I am provided with a shell to this connection

Actual behaviour: VS Code shows an error "The connection could not be opened: Argument #1: Invalid URI: Illegal character [@] found at position 27"

Suggested fix:
Allow usernames which include a "@" -- this is common in my organization.

Thank you for the bug report.  The MySQL Shell for VSCode Extension is no longer supported and has been deprecated in favor of the new MySQL Workbench 26. However, the bug you describe is still present in the new Workbench, so I've updated the bug report to reflect that.