Add "undocumented" need for model Claude Instant

[acornsloth]

Important: Bug reports submitted here should relate specifically to the open source sample amazon-transcribe-live-meeting-assistant project. Do not submit bugs related directly to any AWS service.
If your issue relates to Amazon Transcribe, Amazon Bedrock or Amazon Bedrock Knowledge Base - setup, user provisioning, document ingestion, accuracy, or other aspects of the service, then first check the service documentation, and then reproduce the problem using the relevant AWS service console before engaging AWS support directly. Thank you.

Describe the bug Following the instructions on https://aws.amazon.com/blogs/machine-learning/live-meeting-assistant-with-amazon-transcribe-amazon-bedrock-and-knowledge-bases-for-amazon-bedrock/ to set up Live Meeting Assistant (LMA), specifically, followed instructions of

Before proceeding, if you have not previously done so, you must [request access](https://docs.aws.amazon.com/bedrock/latest/userguide/model-access.html) to the following Amazon Bedrock models:

* Amazon: All Titan Embeddings models (Titan Embeddings G1 – Text, and Titan Text Embeddings V2)
* Anthropic: All Claude 3 models (Claude 3 Sonnet and Claude 3 Haiku)

After that, upon Create stack, the Cloudformation will fail with error, e.g.:

Received response status [FAILED] from custom resource. Message returned: Model(s) '['anthropic.claude-instant-v1']' not available or not enabled. Check that Amazon Bedrock is available in your region, and that required models ('['anthropic.claude-3-haiku-20240307-v1:0', 'amazon.titan-embed-text-v2:0', 'anthropic.claude-3-haiku-20240307-v1:0', 'amazon.titan-embed-text-v1', 'anthropic.claude-instant-v1']') are activated in your Amazon Bedrock account (RequestId: ...)

Indicating the model anthropic.claude-instant-v1 is not enabled, which is not mentioned at all in the documentation. Please add it explicitly in the documentation. Thanks!

To Reproduce Please refer to the section above.

Expected behavior A clear documentation of ALL models that user needs to request access for.

Screenshots N/A

Additional context N/A

[rstrahan]

README updated in v0.1.10 - blog post update to come (or we may remove dependency on Claude Instant which will be better)

[rstrahan]

Blog post is also now updated..