gpui: use a separate image in the image example and remove unnecessary examples (#8181)

Follow-up of https://github.com/zed-industries/zed/pull/8174#issuecomment-1959031659,
Fixes image example and removes window-less "noop" example.

<img width="1975" alt="Screenshot 2024-02-22 at 17 34 15"
src="https://github.com/zed-industries/zed/assets/9134003/060d8484-63b6-415a-9f06-189542422457">

Release Notes:
- N/A

crates/gpui/Cargo.toml

@@ -122,8 +122,4 @@ path = "examples/hello_world.rs"
 
 [[example]]
 name = "image"
-path = "examples/image.rs"
-
-[[example]]
-name = "ownership_post"
-path = "examples/ownership_post.rs"
+path = "examples/image/image.rs"

crates/gpui/examples/image/image.rs

@@ -64,9 +64,8 @@ fn main() {
     App::new().run(|cx: &mut AppContext| {
         cx.open_window(WindowOptions::default(), |cx| {
             cx.new_view(|_cx| ImageShowcase {
-                local_resource: Arc::new(
-                    PathBuf::from_str("crates/zed/resources/app-icon.png").unwrap(),
-                ),
+                // Relative path to your root project path
+                local_resource: Arc::new(PathBuf::from_str("examples/image/app-icon.png").unwrap()),
                 remote_resource: "https://picsum.photos/512/512".into(),
             })
         });