fix(next/font): update axes error logic (#72442)
## Why?
The current error message when you have have a set `weight: ['400', '700']` and set `axes: ['wdth']` for a variable font is confusing—it should mention to correct your weight property (e.g., `weight: 'variable'` or nothing at all for `weight`).
- Fixes https://github.com/vercel/next.js/issues/72413
