Add override for IAM gray overlay

Author: jennantilla

iOS_SDK/OneSignalSDK/OneSignalCore/Source/OneSignalCommonDefines.h

@@ -141,6 +141,7 @@
 #define FALLBACK_TO_SETTINGS_MESSAGE @"Onesignal_settings_fallback_message"
 #define ONESIGNAL_SUPRESS_LAUNCH_URLS @"OneSignal_suppress_launch_urls"
 #define ONESIGNAL_IN_APP_HIDE_DROP_SHADOW @"OneSignal_in_app_message_hide_drop_shadow"
+#define ONESIGNAL_IN_APP_HIDE_GRAY_OVERLAY @"OneSignal_in_app_message_hide_gray_overlay"
 
 // GDPR Privacy Consent
 #define GDPR_CONSENT_GRANTED @"GDPR_CONSENT_GRANTED"

iOS_SDK/OneSignalSDK/OneSignalInAppMessages/UI/OSInAppMessageViewController.m

@@ -184,8 +184,17 @@ - (void)setupInitialMessageUI {
     // Only the center modal and full screen (both centered) IAM should have a dark background
     // So get the alpha based on the IAM being a banner or not
     double alphaBackground = [self.message isBanner] ? 0.0 : 0.5;
-    [UIView animateWithDuration:0.3 animations:^{
+    
+    // the plist value specifies whether the user wants to add a gray overlay to the In App Message
+    NSDictionary *bundleDict = [[NSBundle mainBundle] infoDictionary];
+    BOOL hideGrayOverlay = [bundleDict[ONESIGNAL_IN_APP_HIDE_GRAY_OVERLAY] boolValue];
+    if (hideGrayOverlay) {
+        self.view.backgroundColor = [UIColor clearColor];
+    } else {
         self.view.backgroundColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:alphaBackground];
+    }
+    
+    [UIView animateWithDuration:0.3 animations:^{
         self.view.alpha = 1.0;
     } completion:^(BOOL finished) {
         if (!finished)