bug: unhandled error (InternalServerException) when analysing images larger than 2.5MB

### Checks

- [x] I have searched [github.com/aws/amazon-q-developer-cli/issues](https://github.com/aws/amazon-q-developer-cli/issues?q=) and there are no duplicates of my issue

### Operating system

mac os Sequoia 15.5

### Expected behaviour

I would expect in q chat reported an error about exceeding image file size.

### Actual behaviour

This is the error reported in the q chat:
Amazon Q is having trouble responding right now:
0: unhandled error (InternalServerException)
1: service error
2: unhandled error (InternalServerException)
3: Error { code: "InternalServerException", message: "Encountered an unexpected error when processing the request, please try again.", aws_request_id: "892e6fe5-a769-4fda-8d42-4124d12e8715" }

Location:
crates/chat-cli/src/cli/chat/mod.rs:1215

Backtrace omitted. Run with RUST_BACKTRACE=1 environment variable to display it.
Run with RUST_BACKTRACE=full to include source snippets.

### Steps to reproduce

ask q chat to analyze an image larger than 2.5MB.