FewShotPromptTemplate example formating bug
Labels: name: area: embeddings, name: auto:bug

### System Info
- MacOS 13.4.1 (c) 
- Intel Core i9
#### Version
- Python 3.8.17
- Langchain 0.0.245

#### Context
I am trying build a prompt that convert latex string generated by an OCR algo to a text describing that latex. When using the `FewShotPromptTemplate`, the curly brackets in the latex string are somehow interpreted as key to a dict. 


### Who can help?

@hwchase17 

### Information

- [ ] The official example notebooks/scripts
- [X] My own modified scripts

### Related Components

- [ ] LLMs/Chat Models
- [ ] Embedding Models
- [X] Prompts / Prompt Templates / Prompt Selectors
- [ ] Output Parsers
- [ ] Document Loaders
- [ ] Vector Stores / Retrievers
- [ ] Memory
- [ ] Agents / Agent Executors
- [ ] Tools / Toolkits
- [ ] Chains
- [ ] Callbacks/Tracing
- [ ] Async

### Reproduction

#### Code

```
from langchain.prompts.few_shot import FewShotPromptTemplate
from langchain.prompts.prompt import PromptTemplate

examples = [
  {
    "latex": """\sum_{i=1}^{n}""",
    "doc": """taking sum from 1 to n"""
  }
]

example_template = """
latex: {latex}
doc: {doc}
"""
prefix = """ Convert the latex
"""

suffix = """
User: {latex}
AI: """

example_prompt = PromptTemplate(input_variables=["latex", "doc"], template="Question: {latex}\n{doc}")

few_shot_prompt_template = FewShotPromptTemplate(
    examples=examples,
    example_prompt=example_prompt,
    prefix=prefix,
    suffix=suffix,
    input_variables=["latex"],
    example_separator="\n\n"
)

print(example_prompt.format(**examples[0]))
print(few_shot_prompt_template.format(latex="\frac{a}{b}"))
```

### Expected behavior

#### Error 

The PromptTemplate.format works fine, but the FewShotPromptTemplate fails.
```
---> 34 print(few_shot_prompt_template.format(latex="\frac{a}{b}"))

File [~/Library/Caches/pypoetry/virtualenvs/expression-engine-OXFJOYa8-py3.8/lib/python3.8/site-packages/langchain/prompts/few_shot.py:123](https://file+.vscode-resource.vscode-cdn.net/Users/LLM/~/Library/Caches/pypoetry/virtualenvs/expression-engine-OXFJOYa8-py3.8/lib/python3.8/site-packages/langchain/prompts/few_shot.py:123), in FewShotPromptTemplate.format(self, **kwargs)
    120 template = self.example_separator.join([piece for piece in pieces if piece])
    122 # Format the template with the input variables.
--> 123 return DEFAULT_FORMATTER_MAPPING[self.template_format](template, **kwargs)

File [/usr/local/opt/python](https://file+.vscode-resource.vscode-cdn.net/usr/local/opt/python)@3.8/Frameworks/Python.framework/Versions/3.8/lib/python3.8/string.py:163, in Formatter.format(self, format_string, *args, **kwargs)
    162 def format(self, format_string, [/](https://file+.vscode-resource.vscode-cdn.net/), *args, **kwargs):
--> 163     return self.vformat(format_string, args, kwargs)

File [~/Library/Caches/pypoetry/virtualenvs/expression-engine-OXFJOYa8-py3.8/lib/python3.8/site-packages/langchain/utils/formatting.py:29](https://file+.vscode-resource.vscode-cdn.net/Users/LLM/~/Library/Caches/pypoetry/virtualenvs/expression-engine-OXFJOYa8-py3.8/lib/python3.8/site-packages/langchain/utils/formatting.py:29), in StrictFormatter.vformat(self, format_string, args, kwargs)
     24 if len(args) > 0:
     25     raise ValueError(
     26         "No arguments should be provided, "
...
    227     return args[key]
    228 else:
--> 229     return kwargs[key]

KeyError: 'i=1'
```