DynamoDB deserialization throws exception for big numbers #4693

Describe the bug

This was previously reported at #2500 but that issue was closed and the actions bot recommends creating a new issue which references that.

A number like 1234567895171680000000000000000000000000 is valid in DynamoDB and we're happily persisting such numbers using the golang sdk. But boto3 blows up trying to fetch an item with such a number because it treats the zeros as significant digits.

DYNAMODB_CONTEXT = Context(
    Emin=-128,
    Emax=126,
    prec=38,
    traps=[Clamped, Overflow, Inexact, Rounded, Underflow],
)

...

def _deserialize_n(self, value):
    return DYNAMODB_CONTEXT.create_decimal(value)

Regression Issue

• Select this option if this issue appears to be a regression.

Expected Behavior

Numbers like 1234567895171680000000000000000000000000 are valid in DynamoDB and should be parseable by boto3

Current Behavior

Traceback (most recent call last):
  File "<console>", line 1, in <module>
decimal.Rounded: [<class 'decimal.Rounded'>]

Reproduction Steps

from boto3.dynamodb.types import DYNAMODB_CONTEXT

DYNAMODB_CONTEXT.create_decimal("1234567895171680000000000000000000000000")

Possible Solution

I think it could be fixed using normalize, i.e.

def _deserialize_n(self, value):
    return DYNAMODB_CONTEXT.create_decimal(Decimal(value).normalize())

Additional Information/Context

No response

SDK version used

1.42.23

Environment details (OS name and version, etc.)

MacOS and Ubuntu