Resolve "Fix error shown in formula modal becoming stale after two presses"

Describe the problem

1. Create a formula field
2. Edit it to become invalid sum() for example
3. Click refresh formula options, see the correct first error
4. Edit it again to have a different invalid formula add() for example
5. Click refresh formula options, see that it still shows the old error for the previous formula.

Merge Request Checklist

• changelog.md has been updated if required

Closes #1092 (closed)