Exclude auto-generated schema file from labeler

[ElectronicBlueberry]

Currently we attach the ui/ux label to any PR that changes client files. With the introduction of end-to-end typing however all api changes result in this label being applied, due to the generated schema.ts

This PR excludes said file.

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.