Bump min VS Code version (for Electron 27)

With version of Chromium bundled with Electron 27, the compression plugin files are successfully compiled to WebAssembly on the main thread when loaded.

https://code.visualstudio.com/updates/v1_86#_electron-27-update

package.json

@@ -26,11 +26,8 @@
   "engines": {
     "node": "20.x",
     "pnpm": "8.x",
-    "vscode": ">=1.47.0"
+    "vscode": ">=1.86.0"
   },
-  "activationEvents": [
-    "onCustomEditor:h5web.viewer"
-  ],
   "contributes": {
     "customEditors": [
       {