Export ET_LOG_ENABLED=0 as PUBLIC compile definition on cmake targets (#17907)

The executorch and executorch_core cmake targets did not propagate
ET_LOG_ENABLED=0 to consumers via INTERFACE_COMPILE_DEFINITIONS.
This caused inline/template functions from headers (e.g.
MemoryAllocator::allocate, Result<T>::CheckOk) to be instantiated
with logging enabled in consumer TUs, pulling in format strings,
et_pal_emit_log_message, and the full POSIX logging stack (fprintf,
chrono).

Adding ET_LOG_ENABLED=0 as a PUBLIC definition ensures consumers
compile header code with the same logging state as the library.

Reduces stripped size_test by 4,096 bytes and stripped
size_test_all_ops by 8,192 bytes.

---------

Co-authored-by: Github Executorch <github_executorch@arm.com>

Author: lucylq

CMakeLists.txt

@@ -494,6 +494,9 @@ target_include_directories(
 target_compile_definitions(
   executorch_core PUBLIC C10_USING_CUSTOM_GENERATED_MACROS
 )
+if(NOT EXECUTORCH_ENABLE_LOGGING)
+  target_compile_definitions(executorch_core PUBLIC ET_LOG_ENABLED=0)
+endif()
 target_compile_options(executorch_core PUBLIC ${_common_compile_options})
 if(MAX_KERNEL_NUM)
   target_compile_definitions(
@@ -542,6 +545,9 @@ add_library(executorch ${_executorch__srcs})
 target_link_libraries(executorch PRIVATE executorch_core)
 target_include_directories(executorch PUBLIC ${_common_include_directories})
 target_compile_definitions(executorch PUBLIC C10_USING_CUSTOM_GENERATED_MACROS)
+if(NOT EXECUTORCH_ENABLE_LOGGING)
+  target_compile_definitions(executorch PUBLIC ET_LOG_ENABLED=0)
+endif()
 target_compile_options(executorch PUBLIC ${_common_compile_options})
 executorch_target_link_options_shared_lib(executorch)