Take &mut self in View::render

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

server/src/rpc.rs

@@ -1776,7 +1776,7 @@ mod tests {
             "empty view"
         }
 
-        fn render(&self, _: &mut gpui::RenderContext<Self>) -> gpui::ElementBox {
+        fn render(&mut self, _: &mut gpui::RenderContext<Self>) -> gpui::ElementBox {
             gpui::Element::boxed(gpui::elements::Empty)
         }
     }