fix: public load_auth() fn always called with include_env_var=true (#1961)

Apparently `include_env_var=false` was only used for testing, so clean
up the API a little to make that clear.


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* #1962
* __->__ #1961

codex-rs/cli/src/login.rs

@@ -47,7 +47,7 @@ pub async fn run_login_with_api_key(
 pub async fn run_login_status(cli_config_overrides: CliConfigOverrides) -> ! {
     let config = load_config_or_exit(cli_config_overrides);
 
-    match load_auth(&config.codex_home, true) {
+    match load_auth(&config.codex_home) {
         Ok(Some(auth)) => match auth.mode {
             AuthMode::ApiKey => {
                 if let Some(api_key) = auth.api_key.as_deref() {