Update gh pages deployment for screen reader experiment (test 3) (#3)

* feat: Deploy GH pages w/ screen reader experiment.

* fix: Use correct branch for plugin.

* feat: Introduce initial screen reader support  (experimental) (RaspberryPiFoundation#684)

Fixes part of RaspberryPiFoundation/blockly#3370
Fixes part of RaspberryPiFoundation/blockly#9283

This PR introduces the plugin corresponding changes needed by RaspberryPiFoundation/blockly#9280.

In particular, this:
- Introduces CI workflow updates so that "tip-of-tree" is redefined as the corresponding experimental branch in core for screen reader support (to ensure CI passes here for changes that happen there).
- Removes some access error overrides since the corresponding field was made public in the core PR (which is the root of the CI failures here).
- Introduces some general instructions in the navigation plugin playground for folks testing Blockly with a screen reader (and points to RaspberryPiFoundation#673 for discussion).

**Important**: Note that this PR's changes will NOT be merged into the `main` branch as-is. They will be reconsidered entirely (and likely largely reimplemented) separately from this experimental branch and submitted as a separate, future review for `main`. See RaspberryPiFoundation/blockly#9280 and Fixes part of RaspberryPiFoundation/blockly#9283 for more specifics on why the separate branch thing is being set up this way.

* Revert "feat: Introduce initial screen reader support  (experimental) (RaspberryPiFoundation#684)"

This reverts commit 458e4f8.

Author: BenHenning

.github/workflows/pages.yml

@@ -2,14 +2,16 @@
 name: Deploy static content to Pages
 
 on:
-  # Runs on pushes targeting the default branch
+  # Runs on pushes targeting the default and experimentation branches.
   push:
-    branches: ['main']
+    branches:
+      - main
+      - add-screen-reader-support-experimental
 
-  # Allows you to run this workflow manually from the Actions tab
+  # Allows the workflow to be manually run from the Actions tab.
   workflow_dispatch:
 
-# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
+# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages.
 permissions:
   contents: read
   pages: write
@@ -26,24 +28,37 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout blockly
+      - name: Checkout tip-of-tree core Blockly
         uses: actions/checkout@v4
         with:
           path: blockly
           repository: google/blockly
           ref: develop
 
-      - name: Checkout blockly-keyboard-experimentation
+      - name: Checkout add-screen-reader-support-experimental core Blockly
+        uses: actions/checkout@v4
+        with:
+          path: blockly-add-screen-reader-support-experimental
+          repository: google/blockly
+          ref: add-screen-reader-support-experimental
+
+      - name: Checkout tip-of-tree blockly-keyboard-experimentation
         uses: actions/checkout@v4
         with:
           path: blockly-keyboard-experimentation
 
+      - name: Checkout add-screen-reader-support-experimental blockly-keyboard-experimentation
+        uses: actions/checkout@v4
+        with:
+          path: blockly-keyboard-experimentation-add-screen-reader-support-experimental
+          ref: add-screen-reader-support-experimental
+
       - name: Setup Node
         uses: actions/setup-node@v4
         with:
           node-version: 20.x
 
-      - name: Build blockly
+      - name: Build tip-of-tree core Blockly
         run: |
           cd blockly
           npm ci
@@ -52,19 +67,42 @@ jobs:
           npm link
           cd ../..
 
-      - name: Build blockly-keyboard-experimentation
+      - name: Build tip-of-tree blockly-keyboard-experimentation
         run: |
           cd blockly-keyboard-experimentation
           npm ci
           npm link blockly
           npm run ghpages
+          mkdir ../ghpages
+          cp -r build/* ../ghpages/
+          cd ..
+
+      - name: Build add-screen-reader-support-experimental core Blockly
+        run: |
+          cd blockly/dist
+          npm unlink -g
+          cd ../../blockly-add-screen-reader-support-experimental
+          npm ci
+          npm run package
+          cd dist
+          npm link
+          cd ../..
+
+      - name: Build add-screen-reader-support-experimental blockly-keyboard-experimentation
+        run: |
+          cd blockly-keyboard-experimentation-add-screen-reader-support-experimental
+          npm ci
+          npm link blockly
+          npm run ghpages
+          mkdir ../ghpages/screenreader
+          cp -r build/* ../ghpages/screenreader/
           cd ..
 
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v3
         with:
-          # Upload build folder
-          path: './blockly-keyboard-experimentation/build'
+          # Upload configured GH pages site files.
+          path: './ghpages'
 
   deploy:
     environment: