Tarballs with the ".tar.gz" extension cannot be imported when using "Install package from tarball..."

Reproduction steps:
1. Create a new Unity project
2. Open the Package Manager > + > "Install package from tarball..."
3. Try to select the attached "package.tar.gz"

Expected result: the package can be selected
Actual result: the package cannot be selected

Reproducible with: 2021.3.27f1, 2022.3.4f1, 2023.1.2f1, 2023.2.0a21

Reproducible on: macOS 13.2.1 (Intel)