[wpiutil] Add nested struct schemas before parent schema (#7935)

When adding struct schemas, the current logic is to add the parent/outer schema, and then add the schemas for any nested inner schemas.  This reverses that order to make it easier for tools to process.

Matches C++ logic.

wpiutil/src/main/java/edu/wpi/first/util/datalog/DataLog.java

@@ -451,10 +451,10 @@ public class DataLog implements AutoCloseable {
     if (!seen.add(typeString)) {
       throw new UnsupportedOperationException(typeString + ": circular reference with " + seen);
     }
-    addSchema(typeString, "structschema", struct.getSchema(), timestamp);
     for (Struct<?> inner : struct.getNested()) {
       addSchemaImpl(inner, timestamp, seen);
     }
+    addSchema(typeString, "structschema", struct.getSchema(), timestamp);
     seen.remove(typeString);
   }