Opt in to using experimental Kotlin Native APIs to suppress build warnings (#8885)

- fixes #8846

Author: souma987

kotlin/flatbuffers-kotlin/src/nativeMain/kotlin/com/google/flatbuffers/kotlin/ByteArray.kt

@@ -14,9 +14,12 @@
  * limitations under the License.
  */
 @file:Suppress("NOTHING_TO_INLINE")
+@file:OptIn(ExperimentalNativeApi::class)
 
 package com.google.flatbuffers.kotlin
 
+import kotlin.experimental.ExperimentalNativeApi
+
 /**
  * This implementation assumes that of native macOSX64 the byte order of the implementation is
  * Little Endian.