Add override for IAM drop shadow

Author: jennantilla

OneSignalSDK/onesignal/in-app-messages/src/main/java/com/onesignal/inAppMessages/internal/display/impl/InAppMessageView.kt

@@ -384,7 +384,11 @@ internal class InAppMessageView(
             cardView.cardElevation =
                 0f
         } else {
-            cardView.cardElevation = ViewUtils.dpToPx(5).toFloat()
+            if (getInAppMessageHideDropShadow(context)) {
+                cardView.cardElevation = 0f
+            } else {
+                cardView.cardElevation = ViewUtils.dpToPx(5).toFloat()
+            }
         }
         cardView.radius = ViewUtils.dpToPx(8).toFloat()
         cardView.clipChildren = false
@@ -394,6 +398,10 @@ internal class InAppMessageView(
         return cardView
     }
 
+    private fun getInAppMessageHideDropShadow(context: Context): Boolean {
+        return AndroidUtils.getManifestMetaBoolean(context, "com.onesignal.inAppMessageHideDropShadow")
+    }
+
     /**
      * Schedule dismiss behavior, if IAM has a dismiss after X number of seconds timer.
      */