fix selection fg transform (#2113)

Uses the dpr trick on the selection foreground. Looks like the
background doesn't need this.

### Change Type

- [x] `patch` — Bug fix
- [ ] `minor` — New feature
- [ ] `major` — Breaking change
- [ ] `dependencies` — Changes to package dependencies[^1]
- [ ] `documentation` — Changes to the documentation only[^2]
- [ ] `tests` — Changes to any test code only[^2]
- [ ] `internal` — Any other changes that don't affect the published
package[^2]
- [ ] I don't know

[^1]: publishes a `patch` release, for devDependencies use `internal`
[^2]: will not publish a new version

### Release Notes

- Fixes a small issue causing the selection foreground to be offset when
the browser is at particular zoom levels.

packages/tldraw/src/lib/canvas/TldrawSelectionForeground.tsx

@@ -194,10 +194,10 @@ export const TldrawSelectionForeground: TLSelectionForegroundComponent = track(
 
 		return (
 			<svg
-				ref={rSvg}
+				className="tl-overlays__item tl-selection__fg tl-svg-context"
-				className="tl-overlays__item tl-selection__fg"
 				data-testid="selection-foreground"
 			>
+				<g ref={rSvg}>
 					{shouldDisplayBox && (
 						<rect
 							className={classNames('tl-selection__fg__outline')}
@@ -446,6 +446,7 @@ export const TldrawSelectionForeground: TLSelectionForegroundComponent = track(
 							}}
 						/>
 					)}
+				</g>
 			</svg>
 		)
 	}