restore protoc target from cpm

Author: RayeS2070

cmake/SetupProtobuf.cmake

@@ -60,7 +60,7 @@ if(NOT USERVER_FORCE_DOWNLOAD_PROTOBUF)
 
     if(Protobuf_FOUND)
         _userver_set_protobuf_version_category()
-        set(PROTOBUF_PROTOC $<TARGET_FILE:protobuf::protoc>)
+        set(PROTOBUF_PROTOC "${Protobuf_PROTOC_EXECUTABLE}")
         return()
     endif()
 endif()
@@ -92,3 +92,4 @@ set_target_properties(libprotoc PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${Prot
 write_package_stub(Protobuf)
 mark_targets_as_system("${Protobuf_SOURCE_DIR}")
 _userver_set_protobuf_version_category()
+set(PROTOBUF_PROTOC $<TARGET_FILE:protoc>)