X11: Ensure that VK_SUBOPTIMAL_KHR propagates to user code

Commit 0245b825 switched from returning the error code VK_ERROR_OUT_OF_DATE_KHR to returning the success code VK_SUBOPTIMAL_KHR. Prior to that commit, the error code caused all code paths to fail immediately, but the success code does not.

Currently the success code is not recorded in some scenarios, resulting in a result of VK_SUCCESS instead. This breaks applications that rely on the result (per the spec) to trigger resizes.

This commit ensures that the proper VK_SUBOPTIMAL_KHR success code is set as a sticky status (as comments indicate was intended), ensuring that it is propagated to user code.

Fixes #5331 (closed)