gpui_macos: Migrate `start_external_drag` to `objc2` (#64033)
# Objective
Get rid of instances of the `block` crate, as it will not compile in a
future version of Rust.
## Solution
Migrate an independent code block to the `objc2` crate family.
## Testing
Tested dragging/dropping files & folders from Zed into Finder. There
seems to be some highlighting bug with folders, but that existed
previously as well.
Release Notes:
- N/A
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Co-authored-by: Kirill Bulatov <mail4score@gmail.com>
72c53bf0aatidely committed on 9/10/2026, 2:52:46 PM· committed by GitHubparent7e0b34b