Update documentation for the Context integration with new URL and features (#9259)

Update documentation and URLs for the Langchain Context integration.

We've moved from getcontext.ai to context.ai \o/

Thanks in advance for the review!

docs/extras/integrations/callbacks/context.ipynb

@@ -7,12 +7,12 @@
    "source": [
     "# Context\n",
     "\n",
-    "![Context - Product Analytics for AI Chatbots](https://go.getcontext.ai/langchain.png)\n",
+    "![Context - User Analytics for LLM Powered Products](https://with.context.ai/langchain.png)\n",
     "\n",
-    "[Context](https://getcontext.ai/) provides product analytics for AI chatbots.\n",
+    "[Context](https://context.ai/) provides user analytics for LLM powered products and features.\n",
+    "\n",
+    "With Context, you can start understanding your users and improving their experiences in less than 30 minutes.\n",
     "\n",
-    "Context helps you understand how users are interacting with your AI chat products.\n",
-    "Gain critical insights, optimise poor experiences, and minimise brand risks.\n"
    ]
   },
   {
@@ -55,7 +55,7 @@
     "\n",
     "To get your Context API token:\n",
     "\n",
-    "1. Go to the settings page within your Context account (https://go.getcontext.ai/settings).\n",
+    "1. Go to the settings page within your Context account (https://with.context.ai/settings).\n",
     "2. Generate a new API Token.\n",
     "3. Store this token somewhere secure."
    ]

libs/langchain/langchain/callbacks/context_callback.py

@@ -37,7 +37,7 @@ class ContextCallbackHandler(BaseCallbackHandler):
 
     Keyword Args:
         token (optional): The token with which to authenticate requests to Context.
-            Visit https://go.getcontext.ai/settings to generate a token.
+            Visit https://with.context.ai/settings to generate a token.
             If not provided, the value of the `CONTEXT_TOKEN` environment
             variable will be used.