Add diff-api-snapshot action to danger (#52045)

Summary:
This PR connects breaking change detection with a danger bot. The action takes snapshot from main branch and from the PR as inputs to`diff-api-snapshot` (saved in runner temp directory).

## Changelog:
[Internal]

For more details, see:
https://reactnative.dev/contributing/changelogs-in-pull-requests

Pull Request resolved: https://github.com/facebook/react-native/pull/52045

Reviewed By: huntie

Differential Revision: D76735630

Pulled By: coado

fbshipit-source-id: 9208117340c1e0bf10d58b67892727717d22e62f

.github/actions/diff-js-api-breaking-changes/action.yml

@@ -0,0 +1,23 @@
+name: diff-js-api-breaking-changes
+description: Check for breaking changes in the public React Native JS API
+runs:
+  using: composite
+  steps:
+    - name: Fetch snapshot from PR head
+      shell: bash
+      env:
+        SCRATCH_DIR: ${{ runner.temp }}/diff-js-api-breaking-changes
+      run: |
+        mkdir $SCRATCH_DIR
+        git fetch --depth=1 origin ${{ github.event.pull_request.head.sha }}
+        git show ${{ github.event.pull_request.head.sha }}:packages/react-native/ReactNativeApi.d.ts > $SCRATCH_DIR/ReactNativeApi-after.d.ts \
+          || echo "" > $SCRATCH_DIR/ReactNativeApi.d.ts
+    - name: Run breaking change detection
+      shell: bash
+      env:
+        SCRATCH_DIR: ${{ runner.temp }}/diff-js-api-breaking-changes
+      run: |
+        node ./scripts/diff-api-snapshot \
+        ${{ github.workspace }}/packages/react-native/ReactNativeApi.d.ts  \
+        $SCRATCH_DIR/ReactNativeApi-after.d.ts \
+        > $SCRATCH_DIR/output.json

.github/workflows/danger-pr.yml

@@ -22,6 +22,8 @@ jobs:
         uses: ./.github/actions/setup-node
       - name: Run yarn install
         uses: ./.github/actions/yarn-install
+      - name: Run diff-js-api-breaking-changes
+        uses: ./.github/actions/diff-js-api-breaking-changes
       - name: Danger
         run: yarn danger ci --use-github-checks --failOnErrors
         working-directory: private/react-native-bots