ci: fix `exp/teatest` tests on windows

We did a fix recently about golden files on Windows: https://github.com/charmbracelet/x/pull/365

That fixed many tests on Windows, but on this repository two started failing. We need to figure it out if there is a better way this the below to handle `\r\n` golden files checkout by Git on Windows.

https://github.com/charmbracelet/x/blob/59292a315e5849f674e95c50bd4d2becf9e8ce7f/exp/golden/golden.go#L78-L80

Perhaps we can remove the fix done on #365 and replace it by a `.gitattributes` file instructing Git to preserve `*.golden` files as is? We'd need to do this on all relevant repositories, though, not only on this one.

Start with the two failing exp/teatest tests on Windows and inspect exp/golden/golden.go at lines 78–80, along with the change in pull request #365. Compare the current golden-file handling with the proposed .gitattributes approach, then run the affected tests on Windows and confirm that the golden files behave consistently.

Written by the indexing model from the issue text.