fix: Target proper version of AI SDK for langchain

Author: jsonbailey

packages/ai-providers/server-ai-langchain/package.json

@@ -28,7 +28,7 @@
   "license": "Apache-2.0",
   "dependencies": {
     "@langchain/core": ">=0.2.21 <0.3.0",
-    "@launchdarkly/server-sdk-ai": "0.11.4",
+    "@launchdarkly/server-sdk-ai": "^0.12.0",
     "langchain": "^0.2.11"
   },
   "devDependencies": {