Remove unnecessary duplicative +Sized

PiperOrigin-RevId: 591868644
diff --git a/rust/proxied.rs b/rust/proxied.rs
index 896aba6..2b839fa 100644
--- a/rust/proxied.rs
+++ b/rust/proxied.rs
@@ -90,7 +90,7 @@
 ///
 /// This trait is intentionally made non-object-safe to prevent a potential
 /// future incompatible change.
-pub trait ViewProxy<'msg>: 'msg + Sized + Sync + Unpin + Sized + Debug {
+pub trait ViewProxy<'msg>: 'msg + Sync + Unpin + Sized + Debug {
     type Proxied: 'msg + Proxied + ?Sized;
 
     /// Converts a borrow into a `View` with the lifetime of that borrow.