bug: knowledge add index-type best failing on linux

### 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
- [x] I have run `q doctor` in the affected terminal session
- [x] I have run `q restart` and replicated the issue again

### Operating system

Ubuntu

### Expected behaviour

User should be able to add a new file to the `/knowledge` base with `Best` index type regardless of their machine's operating system

### Actual behaviour

`/knowledge add --index-type Best` would result in `Error: Failed to add: Invalid embedding type 'Best'. Valid options are: fast, best` on Linux, even after changing to `best` (lowercase). The same command works perfectly fine on macOS

### Steps to reproduce

`/knowledge add --index-type Best`
or
`/knowledge add --index-type best`

### Environment

```yaml
[q-details]
version="1.17.1"
hash="52301a3b0f81abff5ecde04a02481734c5c7ecc4"
date="2025-09-30T22:23:06.501414Z+(9d+ago)"
variant="minimal"

[system-info]
chip=""
total-cores=2
memory="7.74+GB"

[system-info.os.linux]
kernel_version="6.8.1-1015-realtime"
id="ubuntu"
name="Ubuntu"
pretty_name="Ubuntu+24.04.2+LTS"
version_id="24.04"
version="24.04.2+LTS+(Noble+Numbat)"

[environment]
cwd="/home/USER"
cli-path="/home/USER"
os="Linux"
shell-path="/usr/bin/zsh"
shell-version="5.9"
install-method="unknown"
```