Reverts "binary_messenger missing cstdint" (#48483)

Reverts #48481
Initiated by: matanlurey
This change reverts the following previous change:
Original Description:
This PR adds cstdint to binary_messenger.h.  Without this building plugin support for generic Linux fails.  Not related to the GTK source tree.

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Author: auto-submit[bot]

shell/platform/common/client_wrapper/include/flutter/binary_messenger.h

@@ -5,7 +5,6 @@
 #ifndef FLUTTER_SHELL_PLATFORM_COMMON_CLIENT_WRAPPER_INCLUDE_FLUTTER_BINARY_MESSENGER_H_
 #define FLUTTER_SHELL_PLATFORM_COMMON_CLIENT_WRAPPER_INCLUDE_FLUTTER_BINARY_MESSENGER_H_
 
-#include <cstdint>
 #include <functional>
 #include <string>