fix(addons): use catch_errors so the update marker is cleared (#18128)

Addons only trapped ERR, so on_exit never ran and ~/.<app>.pending from
fetch_and_deploy_release survived every successful update: each later run
reported 'the last run did not finish' and redeployed. Use catch_errors,
as ct scripts and dockhand.sh already do.


Claude-Session: https://claude.ai/code/session_01BNGzU5KdgKFAGcqJECnnav

Co-authored-by: Matt Daleo <12395090+mazelado@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

tools/addon/coder-code-server.sh

@@ -23,7 +23,7 @@ declare -f init_tool_telemetry &>/dev/null && init_tool_telemetry "coder-code-se
 
 # Enable error handling
 set -Eeuo pipefail
-trap 'error_handler' ERR
+catch_errors
 
 APP="Coder Code Server"
 APP_TYPE="addon"