[Serial] Connection is reset when switching focus

[florenthemmi]

Bug Description

The connection is reset when switching focus (changing tab or window for example).
It is a pain to debug something.

How To Reproduce

Steps to reproduce the behavior:

1. Click on "Show serial"
2. Type something: "import sys"
3. Change tab
4. Module "sys" is not loaded anymore (micro:bit has reset) and all the content is cleared

Expected behavior

Same behavior from previous version: https://python.microbit.org/v/2.
Please note that on the old version the serial is closed only when clicking on the button "Close Serial".

Environment

Desktop:

• OS: MacOS 12.5
• Browser: Chrome
• Version: 103

[microbit-matt-hillsdon]

Thanks @florenthemmi. This is a known issue due to a workaround for #89. We'd love to fix this in future.