feat(macOS): add share menu item

[pewsheen]

What kind of change does this PR introduce?

• [ ] Bugfix
• [x] Feature
• [ ] Docs
• [ ] Code style update
• [ ] Refactor
• [ ] Build-related changes
• [ ] Other, please describe:

Does this PR introduce a breaking change?

• [ ] Yes
• [x] No

Checklist

• [ ] This PR will resolve #___
• [x] A change file is added if any packages will require a version bump due to this PR per the instructions in the readme.
• [ ] I have added a convincing reason for adding this feature, if necessary
• [ ] It can be built on all targets and pass CI/CD.

Other information

Feature request: https://github.com/tauri-apps/tauri/issues/8063