Generated values for settings are a random base64 string with a length of 32. Unfortunately, base64 has some accepted characters like `+` and `/` that don't behave correctly if we use them in a URL without the proper additional encoding.
Use instead this safe version of base64 https://datatracker.ietf.org/doc/html/rfc4648#section-5, where:
- `/` becomes `_`
- `+` becomes `-`
Fixes https://mattermost.atlassian.net/browse/MM-51923
9b81c08622