fix(deps): bump undici to 7.18.2 to mitigate chained decompression (#15221)

Addresses a vulnerability in undici fetch decompression handling where
unbounded Content-Encoding chains could cause excessive CPU and memory
usage.

CVE-2026-22036

Author: rubixvi

packages/payload/package.json

@@ -128,7 +128,7 @@
     "scmp": "2.1.0",
     "ts-essentials": "10.0.3",
     "tsx": "4.20.3",
-    "undici": "7.10.0",
+    "undici": "7.18.2",
     "uuid": "10.0.0",
     "ws": "^8.16.0"
   },