google-auth: reauth: uses deprecated u2f module

### Determine this is the right repository

- [x] I determined this is the correct repository in which to report this bug.

### Summary of the issue

The [reauth extension of google-auth uses pyu2f](https://github.com/googleapis/google-cloud-python/blob/3f70b2ff6f6bc5d4c3bee33784da3e353866ec8e/packages/google-auth/setup.py#L36) but [pyu2f is discontinued](https://github.com/google/pyu2f/blob/3e6ca1666aa0788f124ca5283c9c13045704ca22/README.md?plain=1#L3-L5) and suggests using [Yubico/python-fido2](https://github.com/Yubico/python-fido2) instead, which has backwards compatible support for U2F.

Please switch to that library. Thank you!

(This was previously reported as https://github.com/googleapis/google-cloud-python/issues/15168 but closed without a fix. The problem is still there.)

### API client name and version

google-auth 2.53.0 and git head

### Reproduction steps: code

Code reading.

### Reproduction steps: supporting files

n/a

### Reproduction steps: actual results

n/a

### Reproduction steps: expected results

n/a

### OS & version + platform

all

### Python environment

all

### Python dependencies

n/a

### Additional context

_No response_