add NSPrivacyCollectedDataTypes to Core

* Apparently `NSPrivacyCollectedDataTypes` needs to be in the privacy manifest for Core even though the framework doesn't use any.
* The generated report would say "Missing an expected key: 'NSPrivacyCollectedDataTypes' YourApp.app/Frameworks/OneSignalCore.framework/PrivacyInfo.xcprivacy"

Author: nan-li

iOS_SDK/OneSignalSDK/OneSignalCore/PrivacyInfo.xcprivacy

@@ -2,6 +2,8 @@
 <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
 <dict>
+	<key>NSPrivacyCollectedDataTypes</key>
+	<array/>
 	<key>NSPrivacyAccessedAPITypes</key>
 	<array>
 		<dict>