Add toDynamic conversion function for ImageSource (#52237)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52237

For array props conversion following later in this stack, each type should have a toDynamic conversion available that can be called upon to convert all supported types to a `folly::dynamic` result.

This diff adds the toDynamic conversion function for `ImageSource`

 Changelog: [Internal]

Reviewed By: mdvacca

Differential Revision: D77234063

fbshipit-source-id: 392cbaf172595936f7f66faa824900dadd58bdcf

packages/react-native-codegen/src/generators/components/GeneratePropsCpp.js

@@ -105,7 +105,7 @@ function generatePropsDiffString(
             case 'ImageSourcePrimitive':
               return `
   if (${prop.name} != oldProps->${prop.name}) {
-    result["${prop.name}"] = ${prop.name}.toDynamic();
+    result["${prop.name}"] = toDynamic(${prop.name});
   }`;
             case 'ImageRequestPrimitive':
               // Shouldn't be used in props