fix(overlay): skip disable & upgrade platform (#20647)

This bundles ally.js into Next.js itself to upgrade a dependency they have pinned.

I tried every other major focus trap solution, even those used by some modal libraries, and they all failed.

`ally.js` is the only library that can do it correctly, so we're going to stick with it.

I also removed the `maintain/disabled` as we have a backdrop that would effectively result in the same. This reduces CPU strain.

---

Fixes #19893
Fixes #14369
Closes #14372

packages/react-dev-overlay/package.json

@@ -17,11 +17,12 @@
   },
   "dependencies": {
     "@babel/code-frame": "7.12.11",
-    "ally.js": "1.4.1",
     "anser": "1.4.9",
     "chalk": "4.0.0",
     "classnames": "2.2.6",
+    "css.escape": "1.5.1",
     "data-uri-to-buffer": "3.0.1",
+    "platform": "1.3.6",
     "shell-quote": "1.7.2",
     "source-map": "0.8.0-beta.0",
     "stacktrace-parser": "0.1.10",

packages/react-dev-overlay/src/internal/components/Overlay/Overlay.tsx

@@ -1,7 +1,5 @@
 // @ts-ignore
-import allyDisable from 'ally.js/maintain/disabled'
-// @ts-ignore
-import allyTrap from 'ally.js/maintain/tab-focus'
+import allyTrap from './maintain--tab-focus'
 import * as React from 'react'
 import { lock, unlock } from './body-locker'
 
@@ -29,10 +27,8 @@ const Overlay: React.FC<OverlayProps> = function Overlay({
       return
     }
 
-    const handle1 = allyDisable({ filter: overlay })
     const handle2 = allyTrap({ context: overlay })
     return () => {
-      handle1.disengage()
       handle2.disengage()
     }
   }, [overlay])