Fix: `xdg-desktop-portal-gtk` windowrule improve

[zeerayne]

Pull Request

Description

Some applications somehow spawn xdg-desktop-portal-gtk windows with first capital letter. This small PR consider this in windows rule.

Type of change

Please put an x in the boxes that apply:

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation update (non-breaking change; modified files are limited to the documentations)
• [ ] Technical debt (a code change that does not fix a bug or add a feature but makes something clearer for devs)
• [ ] Other (provide details below)

Checklist

Please put an x in the boxes that apply:

• [x] I have read the CONTRIBUTING document.
• [x] My code follows the code style of this project.
• [x] My commit message follows the commit guidelines.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added a changelog entry.
• [ ] I have added necessary comments/documentation to my code.
• [ ] I have added tests to cover my changes.
• [x] I have tested my code locally and it works as expected.
• [ ] All new and existing tests passed.

Screenshots

This windows was spawned by MeshLab