[test] replace node-libgpiod with serialport in electron-rebuild workflow (#3945)

`node-libgpiod` uses deprecated NAN which is incompatible with Electron
v39+. `serialport` uses N-API ensuring compatibility with current and
future Electron versions.

`node-libgpiod` is only used by 1 of ~1300 3rd-party-modules
(MMM-PresenceScreenControl), while serialport is used by at least 4
modules (MMM-Serial-Notification, MMM-RadarPresence, MMM-LKY-TIC and
MMM-Gestures), making it a better test candidate.

Also updates Electron to v39.

Fixes #3933

.github/workflows/electron-rebuild.yaml

@@ -21,12 +21,8 @@ jobs:
         run: node --run install-mm
       - name: Install @electron/rebuild
         run: npm install @electron/rebuild
-      - name: Install node-libgpiod deps
-        run: |
-          sudo apt-get update
-          sudo apt-get install gpiod libgpiod2 libgpiod-dev
-      - name: Install test library (node-libgpiod) to be rebuilded
-        run: npm install node-libgpiod
+      - name: Install test library (serialport) to be rebuilt
+        run: npm install serialport
       - name: Run electron-rebuild
         run: npx electron-rebuild
         continue-on-error: false