core[patch]: support passing args_schema through as_tool (#24269)

Note: this allows the schema to be passed in positionally.

```python
from langchain_core.pydantic_v1 import BaseModel, Field
from langchain_core.runnables import RunnableLambda


class Add(BaseModel):
    """Add two integers together."""

    a: int = Field(..., description="First integer")
    b: int = Field(..., description="Second integer")


def add(input: dict) -> int:
    return input["a"] + input["b"]


runnable = RunnableLambda(add)
as_tool = runnable.as_tool(Add)
as_tool.args_schema.schema()
```
```
{'title': 'Add',
 'description': 'Add two integers together.',
 'type': 'object',
 'properties': {'a': {'title': 'A',
   'description': 'First integer',
   'type': 'integer'},
  'b': {'title': 'B', 'description': 'Second integer', 'type': 'integer'}},
 'required': ['a', 'b']}
```

docs/docs/how_to/convert_runnable_to_tool.ipynb

@@ -180,7 +180,7 @@
    "id": "32b1a992-8997-4c98-8eb2-c9fe9431b799",
    "metadata": {},
    "source": [
-    "Alternatively, we can add typing information via [Runnable.with_types](https://api.python.langchain.com/en/latest/runnables/langchain_core.runnables.base.Runnable.html#langchain_core.runnables.base.Runnable.with_types):"
+    "Alternatively, the schema can be fully specified by directly passing the desired [args_schema](https://api.python.langchain.com/en/latest/tools/langchain_core.tools.BaseTool.html#langchain_core.tools.BaseTool.args_schema) for the tool:"
    ]
   },
   {
@@ -190,10 +190,18 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "as_tool = runnable.with_types(input_type=Args).as_tool(\n",
-    "    name=\"My tool\",\n",
-    "    description=\"Explanation of when to use tool.\",\n",
-    ")"
+    "from langchain_core.pydantic_v1 import BaseModel, Field\n",
+    "\n",
+    "\n",
+    "class GSchema(BaseModel):\n",
+    "    \"\"\"Apply a function to an integer and list of integers.\"\"\"\n",
+    "\n",
+    "    a: int = Field(..., description=\"Integer\")\n",
+    "    b: List[int] = Field(..., description=\"List of ints\")\n",
+    "\n",
+    "\n",
+    "runnable = RunnableLambda(g)\n",
+    "as_tool = runnable.as_tool(GSchema)"
    ]
   },
   {