fix(aws): resolve Bedrock config errors and optimize credential loading

[akshitkhokhani]

• Fix SigV4AuthScheme missing required 'service' parameter
• Update Config parameters for aws_sdk_bedrock_runtime 0.1.0 compatibility
• Add credential caching to Boto3CredentialsResolver to prevent excessive loading
• Resolves TypeError: SigV4AuthScheme.init() missing 1 required keyword-only argument: 'service'
• Resolves TypeError: Config.init() got an unexpected keyword argument 'http_auth_scheme_resolver'
• Improves performance by eliminating hundreds of unnecessary credential loading calls per second

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[davidzhao]

Thanks for the PR. could you take a look at the failed CI and address the errors?

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