Fix handling UTF-8 object keys (#6373)

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## Summary

<!-- Explain the motivation for this PR. Include "Fixes #<number>" if
applicable. -->

Regarding this
[issue](#6220)
the PR solves it by creating a jsi key string from utf8.

Fixes #6220.

## Test plan

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test out this change along with instructions how to run it and a
description of the expected behavior. -->

Tested on demo provided in issue mentioned above.

---------

Co-authored-by: Tomek Zawadzki <tomekzawadzki98@gmail.com>

packages/react-native-reanimated/Common/cpp/worklets/SharedItems/Shareables.cpp

@@ -233,7 +233,7 @@ ShareableObject::ShareableObject(
 jsi::Value ShareableObject::toJSValue(jsi::Runtime &rt) {
   auto obj = jsi::Object(rt);
   for (size_t i = 0, size = data_.size(); i < size; i++) {
-    obj.setProperty(rt, data_[i].first.c_str(), data_[i].second->toJSValue(rt));
+    obj.setProperty(rt, jsi::String::createFromUtf8(rt, data_[i].first), data_[i].second->toJSValue(rt));
   }
 #if SUPPORTS_NATIVE_STATE
   if (nativeState_ != nullptr) {