chore(CI): fix ecosystem CI failed to get commit sha (#4301)

Author: chenjiahan

.github/workflows/ecosystem-ci.yml

@@ -70,7 +70,7 @@ jobs:
         with:
           script: |
             await github.rest.repos.createCommitComment({
-              commit_sha: github.sha,
+              commit_sha: context.sha,
               owner: 'web-infra-dev',
               repo: 'rsbuild',
               body: ${{ steps.eco-ci-result.outputs.result }}