"Download logs" button should automatically strip color codes

While it is nice to be able to have colors in the output from Spacelift in the UI (and I wish to keep it), when downloading logs for further review (and/or when the logs are too long), the color codes are extremely noisy.

It would be nice to have a preprocessing pass that strips everything before the download.

It is slightly related to 2 other FR but:
- “Disable color injected by Spacelift logger” is more about respecting a “—no-color” flag when passed in a tool,
- “Allow viewing long full plan logs directly from web UI” is more about being able to see all logs in the web UI, and not having to download them (it’s marked as complete, but it doesn’t seem to be the case from my experience?)