The necessary functions to do this were written as part of a broader refactor for better supporting multiple token types. But they were not implemented on the create token screen.
Note: The issue of large number input field was discovered in this diff. I considered splitting it out. However I think this diff is a good demonstration of the issue, and the test here confirms the implementation.
So I think it is worth landing this as a single diff. If we revert, the prod app already has bad alp validation, and we need the precision fix to confirm that with a (good) test.