fix: prevent insertion of nil values in the dictionary (#328)

Closes #38 #89 

RNDeviceInfo/RNDeviceInfo.m

@@ -268,21 +268,21 @@ RCT_EXPORT_MODULE(RNDeviceInfo)
              @"systemName": currentDevice.systemName,
              @"systemVersion": currentDevice.systemVersion,
              @"apiLevel": @"not available",
-             @"model": self.deviceName,
+             @"model": self.deviceName ?: [NSNull null],
              @"brand": @"Apple",
-             @"deviceId": self.deviceId,
+             @"deviceId": self.deviceId ?: [NSNull null],
              @"deviceName": currentDevice.name,
-             @"deviceLocale": self.deviceLocale,
+             @"deviceLocale": self.deviceLocale ?: [NSNull null],
              @"deviceCountry": self.deviceCountry ?: [NSNull null],
              @"uniqueId": uniqueId,
-             @"appName": [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleDisplayName"],
-             @"bundleId": [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleIdentifier"],
+             @"appName": [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleDisplayName"] ?: [NSNull null],
+             @"bundleId": [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleIdentifier"] ?: [NSNull null],
              @"appVersion": [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleShortVersionString"] ?: [NSNull null],
-             @"buildNumber": [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"],
+             @"buildNumber": [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleVersion"] ?: [NSNull null],
              @"systemManufacturer": @"Apple",
              @"carrier": self.carrier ?: [NSNull null],
-             @"userAgent": self.userAgent,
-             @"timezone": self.timezone,
+             @"userAgent": self.userAgent ?: [NSNull null],
+             @"timezone": self.timezone ?: [NSNull null],
              @"isEmulator": @(self.isEmulator),
              @"isTablet": @(self.isTablet),
              @"is24Hour": @(self.is24Hour),