ci: Drop macos-x86_64 build

[kazarmy]

Your checklist for this pull request

• [X] I've read the guidelines for contributing to this repository
• [ ] I made sure to follow the project's coding style
• [ ] I've updated the documentation with the relevant information (if needed)

Detailed description

As in rizinorg/rizin#4676, this pr drops the macos-x86_64 build since Intel Macs have been discontinued and apparently Apple Silicon is exclusively the way of the future.

Test plan (required)

The drop is appropriate.

Closing issues

https://github.com/actions/runner-images/issues/10721

[XVilka]

Is it strictly necessary? I would prefer to keep compatibility as long as possible without too much maintenance.

[kazarmy]

Cutter doesn't get a lot of traffic in terms of prs so I guess it's not strictly necessary.