aws-bedrock v5.3.1 - Unsupported regions for Bedrock custom model are now removed from the regions policy

Bug fixes

• Unsupported regions were inadvertently included in the AWS > Bedrock > Custom Model > Regions policy, which led to the AWS > Bedrock > Custom Model > Discovery control being in an error state for those regions. We've now removed the unsupported regions from the Regions policy.