fix: chromatic workflow failing on forks

Author: JReinhold

.github/workflows/chromatic.yml

@@ -23,7 +23,8 @@ jobs:
         uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
         with:
           fetch-depth: 0
-          ref: ${{ github.event.pull_request.head.ref || github.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name || github.repository }}
+          ref: ${{ github.event.pull_request.head.sha || github.sha }}
 
       - uses: actions/setup-node@6044e13b5dc448c55e2357c09f80417699197238 # v6.2.0
         with: