Fix iOS workflow shell script to use IOS-prefixed env var names

The env block mapped secrets to IOS_-prefixed variables but the shell
script still referenced the old names, causing empty values and a
"Unable to decode the provided data" error during certificate import.

Author: anhappdev

.github/workflows/ios-browserstack-test.yml

@@ -77,15 +77,15 @@ jobs:
           PP_PATH=$RUNNER_TEMP/build_pp.mobileprovision
           KEYCHAIN_PATH=$RUNNER_TEMP/app-signing.keychain-db
 
-          echo -n "$BUILD_CERTIFICATE_BASE64" | base64 --decode -o $CERTIFICATE_PATH
-          echo -n "$BUILD_PROVISION_PROFILE_BASE64" | base64 --decode -o $PP_PATH
+          echo -n "$IOS_BUILD_CERTIFICATE_BASE64" | base64 --decode -o $CERTIFICATE_PATH
+          echo -n "$IOS_BUILD_PROVISION_PROFILE_BASE64" | base64 --decode -o $PP_PATH
 
-          security create-keychain -p "$KEYCHAIN_PASSWORD" $KEYCHAIN_PATH
+          security create-keychain -p "$IOS_KEYCHAIN_PASSWORD" $KEYCHAIN_PATH
           security set-keychain-settings -lut 21600 $KEYCHAIN_PATH
-          security unlock-keychain -p "$KEYCHAIN_PASSWORD" $KEYCHAIN_PATH
+          security unlock-keychain -p "$IOS_KEYCHAIN_PASSWORD" $KEYCHAIN_PATH
 
-          security import $CERTIFICATE_PATH -P "$P12_PASSWORD" -A -t cert -f pkcs12 -k $KEYCHAIN_PATH
-          security set-key-partition-list -S apple-tool:,apple: -k "$KEYCHAIN_PASSWORD" $KEYCHAIN_PATH
+          security import $CERTIFICATE_PATH -P "$IOS_BUILD_CERTIFICATE_PASSWORD" -A -t cert -f pkcs12 -k $KEYCHAIN_PATH
+          security set-key-partition-list -S apple-tool:,apple: -k "$IOS_KEYCHAIN_PASSWORD" $KEYCHAIN_PATH
           security list-keychain -d user -s $KEYCHAIN_PATH
 
           mkdir -p ~/Library/MobileDevice/Provisioning\ Profiles