docs(batch): use newly supported Json model

[heitorlessa]

Issue number: #2090

Summary

Docs leftover from previous PR before release.

Changes

Please provide a summary of what's being changed

Recommends a less verbose option to auto-deserialize Batch records ingested as JSON String for SQS and Kinesis.

User experience

Please share what the user experience looks like before and after this change

BEFORE

import json

from aws_lambda_powertools import Logger, Tracer
from aws_lambda_powertools.utilities.batch import BatchProcessor, EventType, process_partial_response
from aws_lambda_powertools.utilities.parser.models import SqsRecordModel
from aws_lambda_powertools.utilities.typing import LambdaContext
from aws_lambda_powertools.utilities.parser import validator, BaseModel


class Order(BaseModel):
    item: dict

class OrderSqsRecord(SqsRecordModel):
    body: Order

    # auto transform json string
    # so Pydantic can auto-initialize nested Order model
    @validator("body", pre=True)
    def transform_body_to_dict(cls, value: str):
        return json.loads(value)

processor = BatchProcessor(event_type=EventType.SQS, model=OrderSqsRecord)
tracer = Tracer()
logger = Logger()


@tracer.capture_method
def record_handler(record: OrderSqsRecord):
    return record.body.item

@logger.inject_lambda_context
@tracer.capture_lambda_handler
def lambda_handler(event, context: LambdaContext):
    return process_partial_response(event=event, record_handler=record_handler, processor=processor, context=context)

AFTER

import json

from aws_lambda_powertools import Logger, Tracer
from aws_lambda_powertools.utilities.batch import BatchProcessor, EventType, process_partial_response
from aws_lambda_powertools.utilities.parser.models import SqsRecordModel
from aws_lambda_powertools.utilities.typing import LambdaContext
from aws_lambda_powertools.utilities.parser import BaseModel
from aws_lambda_powertools.utilities.parser.types import Json


class Order(BaseModel):
    item: dict

class OrderSqsRecord(SqsRecordModel):
    body: Json[Order]  # deserialize order data from JSON string

processor = BatchProcessor(event_type=EventType.SQS, model=OrderSqsRecord)
tracer = Tracer()
logger = Logger()


@tracer.capture_method
def record_handler(record: OrderSqsRecord):
    return record.body.item

@logger.inject_lambda_context
@tracer.capture_lambda_handler
def lambda_handler(event, context: LambdaContext):
    return process_partial_response(event=event, record_handler=record_handler, processor=processor, context=context)

Checklist

If your change doesn't seem to apply, please leave them unchecked.

• Meet tenets criteria
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• PR title follows conventional commit semantics

Is this a breaking change?

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

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[heitorlessa]

left over, merging before release.