Fix paint_quad behavior change which clamped corner rounding (#27472)

Turns out that git deletion indicator relied on using larger-than-bounds
corner rounding - see
https://github.com/zed-industries/zed/pull/27460#issuecomment-2753174153

Release Notes:

- N/A

crates/gpui/src/elements/img.rs

@@ -421,8 +421,10 @@ impl Element for Img {
             window,
             cx,
             |style, window, cx| {
-                let corner_radii = style.corner_radii.to_pixels(window.rem_size());
-
+                let corner_radii = style
+                    .corner_radii
+                    .to_pixels(window.rem_size())
+                    .clamp_radii_for_quad_size(bounds.size);
                 if let Some(Ok(data)) = source.use_data(window, cx) {
                     let new_bounds = self
                         .style