[BUG] SQS sink `max_message_size` configuration not working

Describe the bug
The max_message_size configuration parameter in SQS sink has no effect. Messages larger than 256KB are rejected regardless of the configured value.

(https://github.com/opensearch-project/data-prepper/blob/8fa41a1025264c0b1b2365f4e7f9064e8ab7aa13/data-prepper-plugins/sqs-sink/src/main/java/org/opensearch/dataprepper/plugins/sink/sqs/SqsSinkBatch.java#L86)
The MAX_BATCH_SIZE_BYTES is hard-coded.

To Reproduce
Steps to reproduce the behavior:

1. Configure SQS sink with max_message_size: 1mb in pipeline configuration
2. Send event as 300kbs through the pipeline
3. Observe that events are still rejected at 256KB limit
4. Check logs - "message":"Event size exceeds max allowed event size".

Expected behavior
When max_message_size is set to 1MB, the SQS sink should accept messages up to 1MB in size, or the configuration should indicate the SQS cannot accept event more than 256kb.

Screenshots
N/A

Environment (please complete the following information):

• OS: [e.g. Ubuntu 20.04 LTS]
• Version [e.g. 22]

Additional context
The issue appears to be in SqsSinkService.java where MAX_EVENT_SIZE and MAX_BYTES_IN_BATCH are hard-coded to 256*1024 bytes, ignoring the configuration parameter.

Start with the referenced SqsSinkBatch.java location and inspect SqsSinkService.java, where the issue reports hard-coded size constants. Reproduce the pipeline using max_message_size: 1mb and a 300KB event, then determine whether the configuration should control the limit or be rejected because of SQS constraints. Done means the configured behavior and error handling match the documented expectation.