Move pb string length method and fix linker error

test/test_atak/test_main.cpp

@@ -2,16 +2,7 @@
 #include <unity.h>
 
 #include "TestUtil.h"
-
-/**
- * Get actual string length for nanopb char array fields.
- * Nanopb stores strings as fixed-size char arrays that may contain embedded nulls.
- * strlen() would stop at the first null, but we need to find the last non-null character.
- * This is critical for Android UIDs that can contain 0x00 bytes (e.g., ANDROID-e7e455b40002429d).
- *
- * Use the firmware implementation declared elsewhere so tests exercise the same logic.
- */
-extern size_t pb_string_length(const char *str, size_t max_len);
+#include "meshUtils.h"
 
 void setUp(void)
 {