`Agents with Chat Models` Example Code Abnormal When Using `google-serper` Tool

### System Info

* Langchain: 0.0.181
* OS: Ubuntu Linux 20.04
  * Kernel: `Linux iZt4n78zs78m7gw0tztt8lZ 5.4.0-47-generic #51-Ubuntu SMP Fri Sep 4 19:50:52 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux`
  * Ubuntu version:
```plain 
LSB Version:    core-11.1.0ubuntu2-noarch:security-11.1.0ubuntu2-noarch
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.1 LTS
Release:        20.04
Codename:       focal
```
* Python: Python 3.8.2

### Who can help?

_No response_

### Information

- [X] The official example notebooks/scripts
- [ ] My own modified scripts

### Related Components

- [ ] LLMs/Chat Models
- [ ] Embedding Models
- [ ] Prompts / Prompt Templates / Prompt Selectors
- [ ] Output Parsers
- [ ] Document Loaders
- [ ] Vector Stores / Retrievers
- [ ] Memory
- [X] Agents / Agent Executors
- [X] Tools / Toolkits
- [ ] Chains
- [ ] Callbacks/Tracing
- [ ] Async

### Reproduction

1. Use the example code provided in [Quick Start: Agents with Chat Models](https://python.langchain.com/en/latest/getting_started/getting_started.html#agents-with-chat-models), but replace the 'serpapi' tool with 'google-serper' tool . 
Here's the modified code:
```python
from langchain.agents import load_tools
from langchain.agents import initialize_agent
from langchain.agents import AgentType
from langchain.chat_models import ChatOpenAI
from langchain.llms import OpenAI

chat = ChatOpenAI(temperature=0.3)

llm = OpenAI(temperature=0)
tools = load_tools(["google-serper", "llm-math"], llm=llm)

agent = initialize_agent(tools, chat, agent=AgentType.CHAT_ZERO_SHOT_REACT_DESCRIPTION, verbose=True)

result = agent.run("Who is Olivia Wilde's boyfriend? What is his current age raised to the 0.23 power?")
print(result)
```

When I execute the code above.  Error occurred.  Here's the error text: 
~~~plain
(openai-test) dsdashun@iZt4n78zs78m7gw0tztt8lZ:~/workspaces/openai-test/langchain$ python3 get_started_chat_agent.py


> Entering new AgentExecutor chain...
Traceback (most recent call last):
  File "/home/dsdashun/.local/share/virtualenvs/openai-test-pldc8tvg/lib/python3.8/site-packages/langchain/agents/chat/output_parser.py", line 22, in parse
    response = json.loads(action.strip())
  File "/usr/lib/python3.8/json/__init__.py", line 357, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python3.8/json/decoder.py", line 340, in decode
    raise JSONDecodeError("Extra data", s, end)
json.decoder.JSONDecodeError: Extra data: line 4 column 2 (char 75)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "get_started_chat_agent.py", line 14, in <module>
    result = agent.run("Who is Olivia Wilde's boyfriend? What is his current age raised to the 0.23 power?")
  File "/home/dsdashun/.local/share/virtualenvs/openai-test-pldc8tvg/lib/python3.8/site-packages/langchain/chains/base.py", line 213, in run
    return self(args[0])[self.output_keys[0]]
  File "/home/dsdashun/.local/share/virtualenvs/openai-test-pldc8tvg/lib/python3.8/site-packages/langchain/chains/base.py", line 116, in __call__
    raise e
  File "/home/dsdashun/.local/share/virtualenvs/openai-test-pldc8tvg/lib/python3.8/site-packages/langchain/chains/base.py", line 113, in __call__
    outputs = self._call(inputs)
  File "/home/dsdashun/.local/share/virtualenvs/openai-test-pldc8tvg/lib/python3.8/site-packages/langchain/agents/agent.py", line 792, in _call
    next_step_output = self._take_next_step(
  File "/home/dsdashun/.local/share/virtualenvs/openai-test-pldc8tvg/lib/python3.8/site-packages/langchain/agents/agent.py", line 672, in _take_next_step
    output = self.agent.plan(intermediate_steps, **inputs)
  File "/home/dsdashun/.local/share/virtualenvs/openai-test-pldc8tvg/lib/python3.8/site-packages/langchain/agents/agent.py", line 385, in plan
    return self.output_parser.parse(full_output)
  File "/home/dsdashun/.local/share/virtualenvs/openai-test-pldc8tvg/lib/python3.8/site-packages/langchain/agents/chat/output_parser.py", line 26, in parse
    raise OutputParserException(f"Could not parse LLM output: {text}")
langchain.schema.OutputParserException: Could not parse LLM output: Question: Who is Olivia Wilde's boyfriend? What is his current age raised to the 0.23 power?
Thought: I should use Serper Search to find out who Olivia Wilde's boyfriend is and then use Calculator to calculate his age raised to the 0.23 power.
Action:
```
{
  "action": "Serper Search",
  "action_input": "Olivia Wilde boyfriend"
},
{
  "action": "Calculator",
  "action_input": "Age of Olivia Wilde's boyfriend raised to the 0.23 power"
}
```

~~~

However, if I use the `pdb` debugger to debug the program step by step, and pause a little bit after running `initialize_agent`, everything is fine.  

I didn't use the 'serpapi' tool, because I don't have an API key on it.  So I cannot verify whether the original example code can be executed successfully on my machine using the 'serpapi' tool

### Expected behavior

I expect the code can run successfully without any problems, even if I replace the search tool with a similar one.