[Bug]: Anthropic Extended Thinking With Tool Use Returns, `Thinking may not be enabled when tool_choice forces tool use`

### Bug Description

- Using Anthropic extended thinking to return **structured output** gives this error: `Thinking may not be enabled when tool_choice forces tool use`
- This also comes up when we force `tool_required=True` for completions. 
- As per this documentation: https://docs.anthropic.com/en/docs/build-with-claude/extended-thinking#extended-thinking-with-tool-use
  > Tool choice limitation: Tool use with thinking only supports tool_choice: {"type": "auto"} (the default) or tool_choice: {"type": "none"}. Using tool_choice: {"type": "any"} or tool_choice: {"type": "tool", "name": "..."} will result in an error because these options force tool use, which is incompatible with extended thinking.
- While, llama index is sending `tool_choice: {"type": "any"}`

### Version

0.13.0

### Steps to Reproduce

Example Code from https://docs.llamaindex.ai/en/stable/examples/llm/anthropic/#structured-prediction and https://docs.llamaindex.ai/en/stable/examples/llm/anthropic/#model-thinking:
```python
from typing import List

from llama_index.llms.anthropic import Anthropic
from llama_index.core.prompts import PromptTemplate
from llama_index.core.bridge.pydantic import BaseModel

from dotenv import load_dotenv
load_dotenv()

class MenuItem(BaseModel):
    """A menu item in a restaurant."""

    course_name: str
    is_vegetarian: bool


class Restaurant(BaseModel):
    """A restaurant with name, city, and cuisine."""

    name: str
    city: str
    cuisine: str
    menu_items: List[MenuItem]


llm = Anthropic(
    model="claude-sonnet-4-0",
    # max_tokens must be greater than budget_tokens
    max_tokens=64000,
    # temperature must be 1.0 for thinking to work
    temperature=1.0,
    thinking_dict={"type": "enabled", "budget_tokens": 1600},
)

prompt_tmpl = PromptTemplate(
    "Generate a restaurant in a given city {city_name}"
)

restaurant_obj = (
    llm.as_structured_llm(Restaurant)
    .complete(prompt_tmpl.format(city_name="Miami"))
    .raw
)

print(restaurant_obj)
```

### Relevant Logs/Tracbacks

```shell
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "~/Projects/amall/main.py", line 42, in <module>
    .complete(prompt_tmpl.format(city_name="Miami"))
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index_instrumentation/dispatcher.py", line 317, in wrapper
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/core/llms/callbacks.py", line 435, in wrapped_llm_predict
    f_return_val = f(_self, *args, **kwargs)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/core/llms/structured_llm.py", line 95, in complete
    return complete_fn(prompt, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/core/base/llms/generic_utils.py", line 184, in wrapper
    chat_response = func(messages, **kwargs)
                    ^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index_instrumentation/dispatcher.py", line 317, in wrapper
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/core/llms/callbacks.py", line 175, in wrapped_llm_chat
    f_return_val = f(_self, messages, **kwargs)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/core/llms/structured_llm.py", line 63, in chat
    output = self.llm.structured_predict(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index_instrumentation/dispatcher.py", line 317, in wrapper
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/core/llms/llm.py", line 360, in structured_predict
    result = program(llm_kwargs=llm_kwargs, **prompt_args)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index_instrumentation/dispatcher.py", line 317, in wrapper
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/core/program/function_program.py", line 151, in __call__
    agent_response = self._llm.predict_and_call(
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index_instrumentation/dispatcher.py", line 317, in wrapper
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/core/llms/function_calling.py", line 228, in predict_and_call
    response = self.chat_with_tools(
               ^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/core/llms/function_calling.py", line 55, in chat_with_tools
    response = self.chat(**chat_kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index_instrumentation/dispatcher.py", line 317, in wrapper
    result = func(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/core/llms/callbacks.py", line 175, in wrapped_llm_chat
    f_return_val = f(_self, messages, **kwargs)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/llama_index/llms/anthropic/base.py", line 393, in chat
    response = self._client.messages.create(
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/anthropic/_utils/_utils.py", line 283, in wrapper
    return func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/anthropic/resources/messages/messages.py", line 997, in create
    return self._post(
           ^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/anthropic/_base_client.py", line 1324, in post
    return cast(ResponseT, self.request(cast_to, opts, stream=stream, stream_cls=stream_cls))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~/Projects/amall/.venv/lib/python3.11/site-packages/anthropic/_base_client.py", line 1112, in request
    raise self._make_status_error_from_response(err.response) from None
anthropic.BadRequestError: Error code: 400 - {'type': 'error', 'error': {'type': 'invalid_request_error', 'message': 'Thinking may not be enabled when tool_choice forces tool use.'}}
```

Labels: bug, triage
State: closed