fix: favor fractional FIL amounts over a larger number of a smaller unit

[lemmih]

205.4 FIL over 205400 milliFIL.

Summary of changes

Changes introduced in this pull request:

• This PR changes the behaviour of the FIL pretty-printer. It's a change in behaviour rather than a bug fix.
• Previously, the pretty-printer tried to find the biggest prefix that yielded a non-fractional number. Eg. 1001 milliFIL over 1.001 FIL. This PR changes the behaviour to find the biggest prefix that yields a number greater than 1.

Reference issue to close (if applicable)

Closes #4951

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

[LesnyRumcajs]

@lemmih no green checkmark!