feat(api): use AsyncMessageDialog for non Linux, closes #7182

[pewsheen]

What kind of change does this PR introduce?

• Bugfix
• Feature
• Docs
• New Binding issue #___
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change?

• Yes, and the changes were approved in issue #___
• No

Checklist

• When resolving issues, they are referenced in the PR's title (e.g fix: remove a typo, closes #___, #___)
• 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

Other information

Issue #7182

This patch is trying to follow how FileDialog deals with the async dialog. Non-Linux systems will use the AsyncMessageDialog.

Tested in macOS, Windows, and Linux. Only macOS will center the dialog.

Although the issue requests to center the dialog on the window, I think someone might want to center the dialog on the screen.

[pewsheen]

Gonna merge to next branch.
I'll open another PR after I pick to https://github.com/tauri-apps/tauri-plugin-dialog