Detach thread in executeAsynchronously (RuntimeExecutor.h) (#31090)

Summary:
std::thread's constructor is nodiscard. This breaks in MSVC 16.9 when nodiscard starts to be enforced. Either we should hold on to the created object or detach the temporary which is what I think this function intends to do anyway.

Fixes #31088

Fixes an invalid usage of std::thread's constructor

## Changelog

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[General] [Fixed] - fixes usage of std::thread in runtime executor

Pull Request resolved: #31090

Reviewed By: sammy-SC

Differential Revision: D26783963

Pulled By: appden

fbshipit-source-id: fed4d072792aafa058dd742e8fce30a207f991c1

Author: asklar

ReactCommon/runtimeexecutor/ReactCommon/RuntimeExecutor.h

@@ -39,9 +39,9 @@ using RuntimeExecutor =
 inline static void executeAsynchronously(
     RuntimeExecutor const &runtimeExecutor,
     std::function<void(jsi::Runtime &runtime)> &&callback) noexcept {
-  std::thread{[callback = std::move(callback), runtimeExecutor]() mutable {
+  std::thread([callback = std::move(callback), runtimeExecutor]() mutable {
     runtimeExecutor(std::move(callback));
-  }};
+  }).detach();
 }
 
 /*