fix(llms): correct the vllm granite model_id

[michael-desmond]

Which issue(s) does this pull-request address?

Cant have a (dot) in ibmvllm backend model id, so the current ibmvllm model_id for granite is incorrect due to the inclusion of a (dot).

Description

• Replaced the (dot) with a dash to match the backend model id.

Checklist

• I have read the contributor guide
• Linting passes: yarn lint or yarn lint:fix
• Formatting is applied: yarn format or yarn format:fix
• Unit tests pass: yarn test:unit
• E2E tests pass: yarn test:e2e
• Tests are included
• Documentation is changed or added
• Commit messages and PR title follow conventional commits