Improves endpoint response type hints, handles all error responses corner case

[spacether]

• Removes last result type hint in endpoint
• Removes generic ApiResponse which is never returned
• Add handling of case when all responses are error codes (4XX or 5XX)
• Used mypy to verify type hints for boolean value with a default per the below mypy check

import typing


@typing.overload
def hi(skip_deserialization: typing.Literal[True]) -> typing.Literal[True]: ...

@typing.overload
def hi(skip_deserialization: typing.Literal[False] = ...) -> typing.Literal[False]: ...

@typing.overload
def hi(skip_deserialization: bool = ...) -> typing.Literal[True, False]: ...

def hi(skip_deserialization: bool = False):
    return skip_deserialization

import random
c: bool = bool(random.randint(0,1))
first = hi()
second = hi(skip_deserialization=True)
third = hi(skip_deserialization=False)
fourth = hi(skip_deserialization=c)

reveal_type(hi())
reveal_type(hi(skip_deserialization=True))
reveal_type(hi(skip_deserialization=False))
reveal_type(hi(skip_deserialization=c))

which resulted in:

overload.py:23: note: Revealed type is "Literal[False]"
overload.py:24: note: Revealed type is "Literal[True]"
overload.py:25: note: Revealed type is "Literal[False]"
overload.py:26: note: Revealed type is "builtins.bool"

So those are how I wrote the skip_deserialization inputs in the type hints
It doesn't work in pycharm because of https://youtrack.jetbrains.com/issue/PY-38074/Ignore-return-types-of-fallback-overloads-for-functions-exactly-matched-by-a-literal-type
but it DOES work in VScode

Corner cases for endpoint response type hinting:

• all error responses should go to -> ApiResponeWithoutDeserialization (this PR adds handling of this case)
• only default response -> ApiResponseForDefault (templates handle this)
• only default response and it is for an error (there is no way to detect this use case)

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