Squash option for Existing MR when Allow and Encourage is selected
For the squash commits options, it states this:
> Set the default behavior and availability of this option in merge requests. **Changes made are also applied to existing merge requests.**
However, this is NOT the current behaviour. `Allow` and `Encourage` does not modify existing merge requests. Whatever is the existing MR setting, it will take that instead.
For example:
| Project Setting | MR setting | Squash Option|
| ------ | ------ | --- |
| Allow (unchecked) | Checked | Checked |
| Encourage (checked) | Unchecked | Unchecked |
☝️ The squash option would adopt whatever is set in the MR setting NOT the project setting.
### Question
Is this the behaviour we want? If yes, then we should look into changing this text. If not, then we need to adjust our logic.
## Background Information
- [ ] @tkuah started a [discussion](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/33827#note_372947588):
> **issue, can handle later, as behind feature flag**
>
> > `Changes made are also applied to existing merge requests.`
>
> This is not accurate. `Allow` and `Encourage` does not modify existing merge requests.
## Related Issue to also consider
_Should there be a single MR state when turning off "Required" squash option_ > https://gitlab.com/gitlab-org/gitlab/-/issues/225277
issue