koyeb instance exec: do not show an error

[brmzkw]

The command koyeb instance exec shows the following error when the connection is interrupted. We should ignore the error, or display a better one:

$ ❌ Error while executing the command: the CLI did not succeed to execute the command

🏥 How to solve the issue?
Make sure the command is correct and exists in the service. If the problem persists, try to update the CLI to the latest version.

🕦 The original error was:
server failure: internal_server_error (code 13)