fix: update outdated document url of exception note

[kdnakt]

Description

This pull request improves Amazon Bedrock model handling with the following changes:

• Fixed broken links.
• Removed error handling for model access (see: https://aws.amazon.com/blogs/security/simplified-amazon-bedrock-model-access/ ).
• Added error handling for invalid model identifiers (see: https://strandsagents.com/docs/user-guide/concepts/model-providers/amazon-bedrock/#model-identifier-is-invalid ).

Related Issues

Documentation PR

Type of Change

Bug fix

Testing

How have you tested the change? Verify that the changes do not break functionality or introduce warnings in consuming repositories: agents-docs, agents-tools, agents-cli

• I ran hatch run prepare

Checklist

• I have read the CONTRIBUTING document
• I have added any necessary tests that prove my fix is effective or my feature works
• I have updated the documentation accordingly
• I have added an appropriate example to the documentation to outline the feature, or no new docs are needed
• My changes generate no new warnings
• Any dependent changes have been merged and published

---

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.