tools: remove Babel from license-builder.sh

Babel is now installed as a dependency in our ESLint installation. The current license-builder.sh will fail to find the license for Babel.

The license is sill present in the repository/code base/file system. So as with all other dependencies that are installed in tools/node_modules/eslint/node_modules and have an MIT license, we are still complying with the license. The inclusion in our own LICENSE was to clearly signal that things under tools/node_modules/@babel were not covered by the Node.js license. Because it is now under tools/node_modules/eslint, that "we aren't the license-holders of this code" aspect of things is already covered by the inclusion of the ESLint license.