[Infra] Use 18.3.1 simulator for Combine integration tests (#14798)

Author: ncooke3

.github/workflows/combine.yml

@@ -14,6 +14,9 @@
 
 name: combine
 
+permissions:
+  contents: read
+
 on:
   workflow_dispatch:
   pull_request:
@@ -48,7 +51,7 @@ concurrency:
 jobs:
   xcodebuild:
     # Don't run on private repo unless it is a PR.
-    if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || github.event_name == 'pull_request'
+    if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || contains(fromJSON('["pull_request", "workflow_dispatch"]'), github.event_name)
     runs-on: macos-15
 
     strategy:
@@ -74,7 +77,7 @@ jobs:
 
   storage-combine-integration:
     # Don't run on private repo unless it is a PR.
-    if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || github.event_name == 'pull_request'
+    if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || contains(fromJSON('["pull_request", "workflow_dispatch"]'), github.event_name)
     env:
       plist_secret: ${{ secrets.GHASecretsGPGPassphrase1 }}
     runs-on: macos-15

scripts/build.sh

@@ -327,8 +327,7 @@ case "$product-$platform-$method" in
       -workspace 'gen/FirebaseCombineSwift/FirebaseCombineSwift.xcworkspace' \
       -scheme "FirebaseCombineSwift-Unit-unit" \
       "${xcb_flags[@]}" \
-      build \
-      test
+      build
     ;;
 
   # TODO(#14760): s/build/test after addressing UI test flakes on CI.
@@ -606,8 +605,8 @@ case "$product-$platform-$method" in
       RunXcodebuild \
         -workspace 'gen/FirebaseCombineSwift/FirebaseCombineSwift.xcworkspace' \
         -scheme "FirebaseCombineSwift-Unit-integration" \
-        "${ios_flags[@]}" \
-        "${xcb_flags[@]}" \
+        -sdk 'iphonesimulator' \
+        -destination 'platform=iOS Simulator,name=iPhone 16,OS=18.3.1' \
         test
       fi
     ;;