fix(gpg-agent): suppress errors from `gpgconf` (#10769)

plugins/gpg-agent/gpg-agent.plugin.zsh

@@ -9,7 +9,7 @@ autoload -U add-zsh-hook
 add-zsh-hook preexec _gpg-agent_update-tty_preexec
 
 # If enable-ssh-support is set, fix ssh agent integration
-if [[ $(gpgconf --list-options gpg-agent | awk -F: '$1=="enable-ssh-support" {print $10}') = 1 ]]; then
+if [[ $(gpgconf --list-options gpg-agent 2>/dev/null | awk -F: '$1=="enable-ssh-support" {print $10}') = 1 ]]; then
   unset SSH_AGENT_PID
   if [[ "${gnupg_SSH_AUTH_SOCK_by:-0}" -ne $$ ]]; then
     export SSH_AUTH_SOCK="$(gpgconf --list-dirs agent-ssh-socket)"