ci(e2e): set up JDK 17 unconditionally (Maestro needs Java to run)

Run 25748105365 confirmed the APK cache hit works — but the Android job
failed with:

  ERROR: Java 17 or higher is required.
  Please update Java, then try again.

Maestro CLI is a JVM app and needs Java 17+ to launch. I had gated the
JDK setup step on cache miss (thinking it was only needed for gradle),
which means on the very first cache hit there's no Java for Maestro.
Remove that gate.

Note: this workflow file change invalidates the source hash, so the next
run is back to cold cache. The run after that will be the actual warm-
cache demonstration.

Author: chriscanin

.github/workflows/mobile-e2e.yml

@@ -218,7 +218,9 @@ jobs:
             | jq '{id, email_addresses: [.email_addresses[].email_address], password_enabled, banned, locked}'
 
       - name: Set up JDK 17
-        if: steps.apk-cache.outputs.cache-hit != 'true'
+        # Always run, not just on cache miss: Maestro itself requires Java 17+
+        # to launch (the maestro CLI is a JVM app). When the APK cache hits
+        # and we skip gradle, we still need Java for the Maestro test step.
         uses: actions/setup-java@v4
         with:
           distribution: temurin