Add availability checks for debug report extension usage

[kocdemir]

Description

Adding the missing condition checks before using the structures and functions from the VK_EXT_debug_report extension in the samples.

Normal functionality should not change when the extension is supported, tested on a device where the extension is missing.

[CLAassistant]

All committers have signed the CLA.

[SaschaWillems]

Thank you very much for your contribution. Note that CI fails at the clang format step, which means you need to properly format your changes with clang-format, see https://github.com/KhronosGroup/Vulkan-Samples/actions/runs/9530177624/job/26297193969?pr=1072

[kocdemir]

Thanks, I've updated the file now.