gpui: Prevent the same action name from being registered multiple times (#33359)

Also removes duplicate `editor::RevertFile` and `vim::HelixDelete`
actions

Release Notes:

- N/A

crates/gpui/src/keymap/context.rs

@@ -432,7 +432,7 @@ mod tests {
             actions!(
                 test_only,
                 [
-                    A, B, C, D, E, F, G, // Don't wrap, test the trailing comma
+                    H, I, J, K, L, M, N, // Don't wrap, test the trailing comma
                 ]
             );
         }