Initially reported from clang-analyzer-core.CallAndMessage, the layer update process in the IPC server was returning a mix of xrt_result_t and bool in various places, to ultimately never make checking the returned value. This commit refactors the layer update function to forward to the layer sync caller the result of every processed layer. Signed-off-by: Simon Zeni <simon.zeni@collabora.com> Part-of: <https://gitlab.freedesktop.org/monado/monado/-/merge_requests/2999>