Pin @a2ui/web_core to <0.8.4 to avoid TextField breakage

web_core 0.8.4 renames TextField's `type` to `textFieldType`
(google#806). Pin until the React renderer is updated to
match (google#810).

Author: lukasmoschitz

renderers/react/package.json

@@ -48,7 +48,7 @@
     "clean": "rm -rf dist"
   },
   "dependencies": {
-    "@a2ui/web_core": "^0.8.0",
+    "@a2ui/web_core": "<0.8.4",
     "clsx": "^2.1.0",
     "markdown-it": "^14.0.0"
   },