linux/x11: disable Vulkan validation in Debug (#8044)

Turns out this validation requirement is confusing new users.

Release Notes:
- N/A

crates/gpui/src/platform/linux/x11/window.rs

@@ -240,7 +240,7 @@ impl X11WindowState {
                 gpu::Context::init_windowed(
                     &raw,
                     gpu::ContextDesc {
-                        validation: cfg!(debug_assertions),
+                        validation: false,
                         capture: false,
                     },
                 )