This is probably better suited to either a question on ROS Answers or the Buildfarm - ROS Discourse category here (maybe a mod can move it there?).

This is a “devel” or “source build” job rather than a packaging job. The build farm configures devel jobs for all repositories by default and builds from the upstream source. If you’re not a maintainer of the package upstream, it’s probably easiest to just turn off the devel and PR jobs on the build farm for the third party package by adding the entries test_commits and test_pull_requests both to false in the source entry for this repository as we do for fastrtps.

I’m not actually sure if clang-tidy is being run. llvm and clang are not being installed in the build environment. It looks like the compiler warnings for this build are being mistaken matched as clang-tidy by the regular expression-based warning parser. As mentioned above, disabling the devel jobs for third party packages (which likely have their own CI infrastructure) is the usual course of action.