Typo fixes in workshop documentation

**Location:**
speech-to-speech/amazon-nova-2-sonic/workshops/README.md
https://github.com/aws-samples/amazon-nova-samples/blob/main/speech-to-speech/amazon-nova-2-sonic/workshops/README.md

**Description:**
There are a couple of minor typographical errors in the Bedrock Knowledge Base (RAG) section of the workshop documentation.

**Proposed fixes:**

intergation → integration
YOUR_KNOLEDGE_BASE_REGION_NAME → YOUR_KNOWLEDGE_BASE_REGION_NAME

Correcting these will improve clarity and reduce potential confusion for users following the workshop steps.

Thank you!