module: tester: Ensure tester module is only built when explicitly selected

Prevent the tester module from being built into the image unless explicitly
configured, especially when it's configured as a loadable module and llext
support is disabled.

Signed-off-by: Adrian Warecki <adrian.warecki@intel.com>

Author: softwarecki

src/debug/tester/CMakeLists.txt

@@ -14,7 +14,7 @@ if(zephyr) ###  Zephyr ###
     add_subdirectory(llext ${PROJECT_BINARY_DIR}/tester_llext)
     add_dependencies(app tester)
 
-  elseif(CONFIG_COMP_TESTER)
+  elseif(CONFIG_COMP_TESTER STREQUAL "y")
 
     zephyr_library_sources(${base_files})