npsl-exception-0.93 is a license not an exception

The file https://github.com/nexB/scancode-toolkit/blob/develop/src/licensedcode/data/licenses/npsl-exception-0.93.LICENSE lists this as an exception, but a look at the license text shows it's actually a license in its own right not an exception that could be added to an existing license.

This is also how it is used in practice e.g. https://rpmfind.net/linux/RPM/fedora/updates/39/aarch64/Packages/n/nmap-ncat-7.95-1.fc39.aarch64.html states the license is LicenseRef-NPSL-0.94 which seems to refer to this license.

The is_exception field should be set to false.