ci(mobile-e2e): scope concurrency by platform so iOS+Android run in parallel

Previous concurrency group was keyed only by github.ref, so dispatches
from both iOS and Android compat gates against the same receiver branch
share the same group. With cancel-in-progress: true, firing the Android
gate cancels an in-flight iOS run (and vice-versa).

Scope the group by which platform's compat gate fired the dispatch
(ios / android / full) so the two can run concurrently. Rapid
re-dispatch within the same scope still cancels (intended behavior).

Author: chriscanin

.github/workflows/mobile-e2e.yml

@@ -73,7 +73,15 @@ env:
   NPM_CONFIG_REGISTRY: https://registry.npmjs.org/
 
 concurrency:
-  group: mobile-e2e-${{ github.ref }}
+  # Scope by platform so iOS and Android compat-gate dispatches can run in
+  # parallel without cancelling each other. A rapid re-dispatch with the
+  # same platform scope still cancels the in-flight one (intended).
+  group: >-
+    mobile-e2e-${{ github.ref }}-${{
+      (inputs.clerk_ios_ref != '' && inputs.clerk_android_ref == '' && 'ios') ||
+      (inputs.clerk_android_ref != '' && inputs.clerk_ios_ref == '' && 'android') ||
+      'full'
+    }}
   cancel-in-progress: true
 
 jobs: