docs: Update IBM docs about information to pass client into WatsonxLLM and WatsonxEmbeddings object. (#24602)

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- [x] **PR title**: Update IBM docs about information to pass client
into WatsonxLLM and WatsonxEmbeddings object.


- [x] **PR message**: 
- **Description:** Update IBM docs about information to pass client into
WatsonxLLM and WatsonxEmbeddings object.


- [x] **Lint and test**: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified. See contribution
guidelines for more: https://python.langchain.com/docs/contributing/

docs/docs/integrations/llms/ibm_watsonx.ipynb

@@ -194,12 +194,37 @@
     ")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "e4a1e0f1",
+   "metadata": {},
+   "source": [
+    "For certain requirements, there is an option to pass the IBM's [`APIClient`](https://ibm.github.io/watsonx-ai-python-sdk/base.html#apiclient) object into the `WatsonxLLM` class."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "4b28afc1",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from ibm_watsonx_ai import APIClient\n",
+    "\n",
+    "api_client = APIClient(...)\n",
+    "\n",
+    "watsonx_llm = WatsonxLLM(\n",
+    "    model_id=\"ibm/granite-13b-instruct-v2\",\n",
+    "    watsonx_client=api_client,\n",
+    ")"
+   ]
+  },
   {
    "cell_type": "markdown",
    "id": "7c4a632b",
    "metadata": {},
    "source": [
-    "You can also pass the IBM's [`ModelInference`](https://ibm.github.io/watsonx-ai-python-sdk/fm_model_inference.html) object into `WatsonxLLM` class."
+    "You can also pass the IBM's [`ModelInference`](https://ibm.github.io/watsonx-ai-python-sdk/fm_model_inference.html) object into the `WatsonxLLM` class."
    ]
   },
   {

docs/docs/integrations/text_embedding/ibm_watsonx.ipynb

@@ -156,6 +156,29 @@
     ")"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "For certain requirements, there is an option to pass the IBM's [`APIClient`](https://ibm.github.io/watsonx-ai-python-sdk/base.html#apiclient) object into the `WatsonxEmbeddings` class."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from ibm_watsonx_ai import APIClient\n",
+    "\n",
+    "api_client = APIClient(...)\n",
+    "\n",
+    "watsonx_llm = WatsonxEmbeddings(\n",
+    "    model_id=\"ibm/slate-125m-english-rtrvr\",\n",
+    "    watsonx_client=api_client,\n",
+    ")"
+   ]
+  },
   {
    "cell_type": "markdown",
    "metadata": {},