Add tests for ReactNativeAttributePayloadFabric.js (#29608)

## Summary

This PR add tests for `ReactNativeAttributePayloadFabric.js`.

It introduces `ReactNativeAttributePayloadFabric-test.internal.js`,
which is a copy-paste of `ReactNativeAttributePayload-test.internal.js`.

On top of that, there is a bunch of new test cases for the
`ReactNativeAttributePayloadFabric.create` function.

## How did you test this change?

```
yarn test packages/react-native-renderer
```

Author: dmytrorykun

packages/react-native-renderer/src/ReactNativeAttributePayloadFabric.js

@@ -449,17 +449,24 @@ function fastAddProperties(
   props: Object,
   validAttributes: AttributeConfiguration,
 ): null | Object {
-  let attributeConfig;
-  let prop;
+  // Flatten nested style props.
+  if (isArray(props)) {
+    for (let i = 0; i < props.length; i++) {
+      payload = fastAddProperties(payload, props[i], validAttributes);
+    }
+    return payload;
+  }
 
   for (const propKey in props) {
-    prop = props[propKey];
+    const prop = props[propKey];
 
     if (prop === undefined) {
       continue;
     }
 
-    attributeConfig = ((validAttributes[propKey]: any): AttributeConfiguration);
+    const attributeConfig = ((validAttributes[
+      propKey
+    ]: any): AttributeConfiguration);
 
     if (attributeConfig == null) {
       continue;
@@ -477,7 +484,7 @@ function fastAddProperties(
       // An atomic prop with custom processing.
       newValue = attributeConfig.process(prop);
     } else if (typeof attributeConfig.diff === 'function') {
-      // An atomic prop with custom diffing. We don't do diffing here.
+      // An atomic prop with custom diffing. We don't need to do diffing when adding props.
       newValue = prop;
     }
 
@@ -489,17 +496,6 @@ function fastAddProperties(
       continue;
     }
 
-    // Not-atomic prop that needs to be flattened. Likely it's the 'style' prop.
-
-    // It can be an array.
-    if (isArray(prop)) {
-      for (let i = 0; i < prop.length; i++) {
-        payload = fastAddProperties(payload, prop[i], attributeConfig);
-      }
-      continue;
-    }
-
-    // Or it can be an object.
     payload = fastAddProperties(payload, prop, attributeConfig);
   }
 
@@ -514,11 +510,7 @@ function addProperties(
   props: Object,
   validAttributes: AttributeConfiguration,
 ): null | Object {
-  if (enableAddPropertiesFastPath) {
-    return fastAddProperties(updatePayload, props, validAttributes);
-  } else {
-    return diffProperties(updatePayload, emptyObject, props, validAttributes);
-  }
+  return diffProperties(updatePayload, emptyObject, props, validAttributes);
 }
 
 /**
@@ -538,11 +530,11 @@ export function create(
   props: Object,
   validAttributes: AttributeConfiguration,
 ): null | Object {
-  return addProperties(
-    null, // updatePayload
-    props,
-    validAttributes,
-  );
+  if (enableAddPropertiesFastPath) {
+    return fastAddProperties(null, props, validAttributes);
+  } else {
+    return addProperties(null, props, validAttributes);
+  }
 }
 
 export function diff(