Drop removed download_mode field from target-ambiguity test

main's new in_process_target_ambiguity test (#1034) sets
GlobalArgs::download_mode, which this PR deletes, so the merge at
d06ce6f does not compile the cli test targets.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: claude

crates/socket-patch-cli/tests/in_process_target_ambiguity.rs

@@ -210,7 +210,6 @@ fn get_args(identifier: &str, cwd: &Path, api_url: String) -> GetArgs {
             api_token: Some("fake-token-for-tests".to_string()),
             api_url: Some(api_url),
             json: true,
-            download_mode: "diff".to_string(),
             ..socket_patch_cli::args::GlobalArgs::default()
         },
         identifier: identifier.to_string(),