AmazonBedrockChatGenerator is not working with the Mixtral model

[vish9812]

Describe the bug
Calling run with the Mixtral model - mistral.mixtral-8x7b-instruct-v0:1 is failing with the following error message: Could not inference Amazon Bedrock model mistral.mixtral-8x7b-instruct-v0:1 due: An error occurred (ValidationException) when calling the InvokeModel operation: Validation Error.

While the code runs successfully with the Mistral model - mistral.mistral-7b-instruct-v0:2.

To Reproduce

AmazonBedrockChatGenerator(
            # model="mistral.mistral-7b-instruct-v0:2", It passes
            # model="mistral.mixtral-8x7b-instruct-v0:1", It fails
).run(prompt)

Describe your environment (please complete the following information):

• OS: Ubuntu 22.04
• Haystack version: 2.1.2
• Integration version: 0.7.1

PS: I've access to both the models, so, it's not an access issue.

[anakin87]

duplicate of #732

[vish9812]

@anakin87 Actually, this is a different issue. I'm able to run inference for the MiStral Model via HF access token.
But the issue here is that while the MiStral model works fine. The MiXtral model gives the above mentioned validation error.