vk_texture_runtime: Fix debug scope label lambda-capture (#7102)

`DebugScope` was capturing a `string_view` in a lambda which is only
valid during the scope of this ctor. When the lambda gets invoked at a
later time, it will read undefined garbage. The lambda needs to make a
deep copy of this `string_view` into a `string` so that it is valid by
the time the scheduler invokes this lambda.

src/video_core/renderer_vulkan/vk_texture_runtime.cpp

@@ -1562,7 +1562,7 @@ DebugScope::DebugScope(TextureRuntime& runtime, Common::Vec4f color, std::string
     if (!has_debug_tool) {
         return;
     }
-    scheduler.Record([color, label](vk::CommandBuffer cmdbuf) {
+    scheduler.Record([color, label = std::string(label)](vk::CommandBuffer cmdbuf) {
         const vk::DebugUtilsLabelEXT debug_label = {
             .pLabelName = label.data(),
             .color = std::array{color[0], color[1], color[2], color[3]},