Meta+LibJS: Update fast-float to version 8.1.0

This release comes with a fix for a bug where certain unicode emoji
characters were coerced into an integer when put into the key of an JS
object, i.e. `{ "⤵️": 42 }` would become `{ "5": 42 }`.

Relevant upstream PR: fastfloat/fast_float#325

Author: InvalidUsernameException

Libraries/LibJS/Tests/object-with-unicode-emoji-as-key.js

@@ -0,0 +1,25 @@
+test("unicode emojis with the low byte corresponding to the value of an ascii digit should not coerce to integers", () => {
+    const emojis = [
+        "ℹ",
+        "ℹ️",
+        "☸",
+        "☸️",
+        "☹",
+        "☹️",
+        "✳",
+        "✳️",
+        "✴",
+        "✴️",
+        "⤴",
+        "⤴️",
+        "⤵",
+        "⤵️",
+        "〰",
+        "〰️",
+    ];
+    for (const emoji of emojis) {
+        const o = {};
+        o[emoji] = 42;
+        expect(Object.keys(o)[0]).toBe(emoji);
+    }
+});

vcpkg.json

@@ -220,7 +220,7 @@
     },
     {
       "name": "fast-float",
-      "version": "8.0.2#0"
+      "version": "8.1.0#0"
     },
     {
       "name": "ffmpeg",