'graphqlError.extensions' is possibly 'undefined' in enrichError()
### Issue Description

https://github.com/apollographql/apollo-server/blob/252cb380bf84efb1688e5d8e4a64af42e467c787/packages/server/src/errorNormalize.ts#L64

'graphqlError.extensions' is possibly 'undefined'.

run into `Cannot read properties of undefined` error. 

### Link to Reproduction

The error can be seen compile time.
<img width="729" alt="image" src="https://github.com/apollographql/apollo-server/assets/86254270/08b12960-e20b-4fac-a6c0-c3638eccac95">


full error that apollo server returned:

<img width="1563" alt="image" src="https://github.com/apollographql/apollo-server/assets/86254270/1914ef94-bcd3-44c4-8539-7b2d403e0a6c">

### Reproduction Steps

_No response_