menus: address several little big things about menu styling (#2624)

- menu: fix accidental stacking of menus
https://linear.app/tldraw/issue/TLD-2077/radix-menus-double-submenu
which is a followup to https://github.com/tldraw/tldraw/pull/2101
- cc @steveruizok I might be missing context here but looking at the
original PR I don't see why this is needed anymore? can you show me in
person?
- menu: rework checkboxes
https://linear.app/tldraw/issue/TLD-2071/improve-appearance-of-menu-checkboxes
- menu: nix the text-shadow on menus
- menu: fix the kbd being off by a couple pixels

### Change Type

- [x] `patch` — Bug fix

### Release Notes

- Fixes nits on styling on our Radix menus.

assets/icons/icon/checkbox-empty.svg

@@ -1,3 +1,19 @@
-<svg width="30" height="30" viewBox="0 0 30 30" fill="none" xmlns="http://www.w3.org/2000/svg">
-<path d="M8 8H22V22H8V8Z" stroke="black" stroke-opacity="0.5" stroke-width="2"/>
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   width="30"
+   height="30"
+   viewBox="0 0 30 30"
+   fill="none"
+   version="1.1"
+   id="svg1"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:svg="http://www.w3.org/2000/svg">
+  <defs
+     id="defs1" />
+  <path
+     d="M 6.4651362,4.9397125 H 23.974196 a 1.7194619,1.7194619 45 0 1 1.719462,1.7194619 l 0,17.5090556 a 1.779661,1.779661 135 0 1 -1.779661,1.779661 H 6.5922549 A 1.9067797,1.9067797 45 0 1 4.6854752,24.041111 V 6.7193735 a 1.779661,1.779661 135 0 1 1.779661,-1.779661 z"
+     stroke="#000000"
+     stroke-width="3"
+     id="path1"
+     transform="translate(0.81043485,0.55619755)" />
 </svg>

packages/tldraw/src/lib/ui.css

@@ -33,7 +33,6 @@
 	font-size: 12px;
 	gap: 0px;
 	color: var(--color-text-1);
-	text-shadow: 1px 1px var(--color-text-shadow);
 }
 
 .tlui-button:disabled {
@@ -528,6 +527,10 @@
 	border-radius: 2px;
 }
 
+.tlui-kbd > span:last-child {
+	padding-right: 0;
+}
+
 .tlui-kbd:not(:last-child) {
 	margin-right: var(--space-2);
 }

packages/tldraw/src/lib/ui/hooks/useMenuIsOpen.ts

@@ -8,15 +8,8 @@ export function useMenuIsOpen(id: string, cb?: (isOpen: boolean) => void) {
 	const rIsOpen = useRef(false)
 	const trackEvent = useUiEvents()
 
-	const rLastChange = useRef(0)
-
 	const onOpenChange = useCallback(
 		(isOpen: boolean) => {
-			// prevent multiple calls in quick succession
-			const now = Date.now()
-			if (now - rLastChange.current < 50) return
-			rLastChange.current = now
-
 			rIsOpen.current = isOpen
 
 			editor.batch(() => {