bad gens for Free algebras over inexact rings

[fchapoton]

Steps To Reproduce

No response

Expected Behavior

Avoid the numerical constant in front of the gens when possible

Actual Behavior

Here is the issue:

sage: A=FreeAlgebra(CC,['a','b'])
sage: A
Free Algebra on 2 generators (1.00000000000000*a, 1.00000000000000*b) over Complex Field with 53 bits of precision
sage: A.gens()
(1.00000000000000*a, 1.00000000000000*b)
sage: A.gen(0)
1.00000000000000*a

This make the following fail:
GradedCommutativeAlgebra(CC,degrees=(Integer(1),Integer(1)), names=('a', 'b',))

Additional Information

Taken from https://stackoverflow.com/questions/77367021/

Environment

- **OS**:
- **Sage Version**:

Checklist

• I have searched the existing issues for a bug report that matches the one I want to file, without success.
• I have read the documentation and troubleshoot guide

[tscrim]

I believe we could fix this by passing self.variable_names() along instead of self.gens().