fix(ci): remove spaces in GitHub Actions variable expansion syntax

React Native, React Native Expo, and Flutter workflows had incorrect
syntax with spaces in variable references:
  PR_NUMBER="${ github.event.pull_request.number }"

This caused variables to not expand, resulting in empty PR_NUMBER
values and fallback to generic "Build #123" format on BrowserStack
instead of "PR-185: [title] - [message]" format.

Fixed to correct syntax:
  PR_NUMBER="${{ github.event.pull_request.number }}"

Applied to:
- react-native-ci.yml (Android + iOS sections)
- react-native-expo-ci.yml (Android + iOS sections)
- flutter-ci.yml (Android + iOS sections)

Author: teodorciuraru

.github/workflows/flutter-ci.yml

@@ -509,9 +509,9 @@ jobs:
             DEVICES=$(yq eval -o=json -I=0 '.flutter.android.devices' .github/browserstack-devices.yml)
 
             # Build BrowserStack project/build names with PR context
-            PR_NUMBER="${ github.event.pull_request.number }"
-            PR_TITLE="${ github.event.pull_request.title }"
-            COMMIT_MSG="${ github.event.head_commit.message }"
+            PR_NUMBER="${{ github.event.pull_request.number }}"
+            PR_TITLE="${{ github.event.pull_request.title }}"
+            COMMIT_MSG="${{ github.event.head_commit.message }}"
 
             # Sanitize - keep only BrowserStack-allowed chars: A-Z a-z 0-9 . : - [ ] / @ & ' _
             PR_TITLE_CLEAN=$(echo "$PR_TITLE" | sed "s/[^A-Za-z0-9.:[\]\/@&' _-]//g")
@@ -793,9 +793,9 @@ jobs:
             DEVICES=$(yq eval -o=json -I=0 '.flutter.ios.devices' .github/browserstack-devices.yml)
 
             # Build BrowserStack project/build names with PR context
-            PR_NUMBER="${ github.event.pull_request.number }"
-            PR_TITLE="${ github.event.pull_request.title }"
-            COMMIT_MSG="${ github.event.head_commit.message }"
+            PR_NUMBER="${{ github.event.pull_request.number }}"
+            PR_TITLE="${{ github.event.pull_request.title }}"
+            COMMIT_MSG="${{ github.event.head_commit.message }}"
 
             # Sanitize - keep only BrowserStack-allowed chars: A-Z a-z 0-9 . : - [ ] / @ & ' _
             PR_TITLE_CLEAN=$(echo "$PR_TITLE" | sed "s/[^A-Za-z0-9.:[\]\/@&' _-]//g")

.github/workflows/react-native-ci.yml

@@ -306,9 +306,9 @@ jobs:
             echo "Loaded devices: $DEVICES"
 
             # Build BrowserStack project/build names with PR context
-            PR_NUMBER="${ github.event.pull_request.number }"
-            PR_TITLE="${ github.event.pull_request.title }"
-            COMMIT_MSG="${ github.event.head_commit.message }"
+            PR_NUMBER="${{ github.event.pull_request.number }}"
+            PR_TITLE="${{ github.event.pull_request.title }}"
+            COMMIT_MSG="${{ github.event.head_commit.message }}"
 
             # Sanitize - keep only BrowserStack-allowed chars: A-Z a-z 0-9 . : - [ ] / @ & ' _
             PR_TITLE_CLEAN=$(echo "$PR_TITLE" | sed "s/[^A-Za-z0-9.:[\]\/@&' _-]//g")
@@ -510,9 +510,9 @@ jobs:
             echo "Loaded devices: $DEVICES"
 
             # Build BrowserStack project/build names with PR context
-            PR_NUMBER="${ github.event.pull_request.number }"
-            PR_TITLE="${ github.event.pull_request.title }"
-            COMMIT_MSG="${ github.event.head_commit.message }"
+            PR_NUMBER="${{ github.event.pull_request.number }}"
+            PR_TITLE="${{ github.event.pull_request.title }}"
+            COMMIT_MSG="${{ github.event.head_commit.message }}"
 
             # Sanitize - keep only BrowserStack-allowed chars: A-Z a-z 0-9 . : - [ ] / @ & ' _
             PR_TITLE_CLEAN=$(echo "$PR_TITLE" | sed "s/[^A-Za-z0-9.:[\]\/@&' _-]//g")

.github/workflows/react-native-expo-ci.yml

@@ -313,9 +313,9 @@ jobs:
             echo "Loaded devices: $DEVICES"
 
             # Build BrowserStack project/build names with PR context
-            PR_NUMBER="${ github.event.pull_request.number }"
-            PR_TITLE="${ github.event.pull_request.title }"
-            COMMIT_MSG="${ github.event.head_commit.message }"
+            PR_NUMBER="${{ github.event.pull_request.number }}"
+            PR_TITLE="${{ github.event.pull_request.title }}"
+            COMMIT_MSG="${{ github.event.head_commit.message }}"
 
             # Sanitize - keep only BrowserStack-allowed chars: A-Z a-z 0-9 . : - [ ] / @ & ' _
             PR_TITLE_CLEAN=$(echo "$PR_TITLE" | sed "s/[^A-Za-z0-9.:[\]\/@&' _-]//g")
@@ -517,9 +517,9 @@ jobs:
             echo "Loaded devices: $DEVICES"
 
             # Build BrowserStack project/build names with PR context
-            PR_NUMBER="${ github.event.pull_request.number }"
-            PR_TITLE="${ github.event.pull_request.title }"
-            COMMIT_MSG="${ github.event.head_commit.message }"
+            PR_NUMBER="${{ github.event.pull_request.number }}"
+            PR_TITLE="${{ github.event.pull_request.title }}"
+            COMMIT_MSG="${{ github.event.head_commit.message }}"
 
             # Sanitize - keep only BrowserStack-allowed chars: A-Z a-z 0-9 . : - [ ] / @ & ' _
             PR_TITLE_CLEAN=$(echo "$PR_TITLE" | sed "s/[^A-Za-z0-9.:[\]\/@&' _-]//g")