use as_deref instead of as_ref for account.name

Reasons:
- More concise.
- Avoids the need for map(String::str).

Signed-off-by: Perma Alesheikh <me@prma.dev>

src/folder/command/delete.rs

@@ -51,7 +51,7 @@ impl FolderDeleteCommand {
         };
 
         let (toml_account_config, account_config) = config.clone().into_account_configs(
-            self.account.name.as_ref().map(String::as_str),
+            self.account.name.as_deref(),
             #[cfg(feature = "account-sync")]
             self.cache.disable,
         )?;