ci(model-profiles): skip profile refresh workflow on forks (#38008)

Closes #37997

Forked repositories with Actions enabled currently run the scheduled
model profile refresh without access to the GitHub App secrets used to
open the automated PR. Guarding the job to the `langchain-ai` owner
prevents noisy daily failures on forks while preserving the scheduled
refresh for the main repository.

## Changes
- Added a repository-owner guard to the `refresh-profiles` job so
`refresh_model_profiles` only runs under `langchain-ai`.
- Kept the existing reusable workflow invocation and bot secret wiring
unchanged for the canonical repository.

.github/workflows/refresh_model_profiles.yml

@@ -18,6 +18,7 @@ permissions:
 
 jobs:
   refresh-profiles:
+    if: github.repository_owner == 'langchain-ai'
     uses: ./.github/workflows/_refresh_model_profiles.yml
     with:
       providers: >-