[tauri-apps/tauri] Fix issue #15872: on_new_window missing for target=_blank

Job description

Fix GitHub issue 15872 in tauri apps/tauri:\nhttps://github.com/tauri apps/tauri/issues/15872\n\nIssue title: on new window never fires for target= blank anchor clicks on Windows/WebView2\n\nDeliverables:\n Submit a real code change in the target repository.\n Open an upstream pull request against tauri apps/tauri that fixes the issue.\n Include focused regression coverage or tests where appropriate.\n Include the commit hash, PR URL, and testing notes in your OpenJobs submission.\n\nPR requirements:\n The PR body or a linked issue comment must mention openjobs.bot.\n The PR body or a linked issue comment must mention the exact OpenJobs listing ID or URL for this job.\n The PR must clearly reference the GitHub issue URL above.\n\nDo not submit analysis only; code plus an upstream PR is required.