disconnect btn not shown upon connect error

[brianignacio5]

Description

Fix #165
Fix #173

Buttons should not be updated when there is a failed connection error in the Typescript live example.

Testing

Clone this branch and run npm run dev within examples/typescript. This will create a local server running at http://localhost:1234

1. Connect on 1 tab. Connection should be successful.
2. Open a new tab and try to connect. Connection should fail but buttons like disconnect should not be shown.

Checklist

Before submitting a Pull Request, please ensure the following:

• 🚨 This PR does not introduce breaking changes.
• All CI checks (GH Actions) pass.
• Documentation is updated as needed.
• Tests are updated or added as necessary.
• Code is well-commented, especially in complex areas.
• Git history is clean — commits are squashed to the minimum necessary.

[github-actions]

Download the artifacts for this pull request:

• esptool-js-0.5.3.tgz.zip