Remove some redundant entity clones (#36274)

`cx.entity()` already returns an owned entity, so there is no need for
these clones.

Release Notes:

- N/A

crates/extensions_ui/src/extensions_ui.rs

@@ -703,7 +703,7 @@ impl ExtensionsPage {
         extension: &ExtensionMetadata,
         cx: &mut Context<Self>,
     ) -> ExtensionCard {
-        let this = cx.entity().clone();
+        let this = cx.entity();
         let status = Self::extension_status(&extension.id, cx);
         let has_dev_extension = Self::dev_extension_exists(&extension.id, cx);