[ci] Adjust workflow for dispatching go_router batch release (#10733)

I think this is what was missing, the current error message without this patch https://github.com/flutter/packages/actions/runs/20761184331

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Author: chunhtai

.github/workflows/batch_release_pr.yml

@@ -2,7 +2,7 @@ name: "Creates Batch Release for a Package"
 
 on:
   repository_dispatch:
-    types: [batch_release_pr]
+    types: [batch-release-pr]
 
 jobs:
   create_release_pr:

.github/workflows/go_router_batch.yml

@@ -10,10 +10,11 @@ on:
 jobs:
   dispatch_release_pr:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
     steps:
       - name: Repository Dispatch
         uses: peter-evans/repository-dispatch@5fc4efd1a4797ddb68ffd0714a238564e4cc0e6f
         with:
-          token: "${{ secrets.GITHUB_TOKEN }}"
-          event-type: batch_release_pr
+          event-type: batch-release-pr
           client-payload: '{"package": "go_router"}'