Remove obsolete feature flags

- already removed in Bitwarden:
https://github.com/bitwarden/server/pull/3692
https://github.com/bitwarden/server/pull/4083

src/config.rs

@@ -800,9 +800,7 @@ fn validate_config(cfg: &ConfigItems) -> Result<(), Error> {
         }
     }
 
-    // TODO: deal with deprecated flags so they can be removed from this list, cf. #4263
-    const KNOWN_FLAGS: &[&str] =
-        &["autofill-overlay", "autofill-v2", "browser-fileless-import", "fido2-vault-credentials"];
+    const KNOWN_FLAGS: &[&str] = &["browser-fileless-import"];
     let configured_flags = parse_experimental_client_feature_flags(&cfg.experimental_client_feature_flags);
     let invalid_flags: Vec<_> = configured_flags.keys().filter(|flag| !KNOWN_FLAGS.contains(&flag.as_str())).collect();
     if !invalid_flags.is_empty() {