Remove extra space in zed --version string for non-stable (#24254)

Release Notes:

- N/A

crates/cli/src/main.rs

@@ -343,7 +343,7 @@ mod linux {
                 if *RELEASE_CHANNEL == "stable" {
                     "".to_string()
                 } else {
-                    format!(" {} ", *RELEASE_CHANNEL)
+                    format!("{} ", *RELEASE_CHANNEL)
                 },
                 option_env!("RELEASE_VERSION").unwrap_or_default(),
                 self.0.display(),