chore(async): reenable async prompt by default on zsh < 5.0.6 (#12358)

Fixes #12331

lib/git.zsh

@@ -39,21 +39,17 @@ function _omz_git_prompt_info() {
   echo "${ZSH_THEME_GIT_PROMPT_PREFIX}${ref:gs/%/%%}${upstream:gs/%/%%}$(parse_git_dirty)${ZSH_THEME_GIT_PROMPT_SUFFIX}"
 }
 
-# Use async version if setting is enabled, or undefined but zsh version is at least 5.0.6
-# https://github.com/ohmyzsh/ohmyzsh/issues/12331#issuecomment-2059460268
-if zstyle -t ':omz:alpha:lib:git' async-prompt \
-  || { is-at-least 5.0.6 && zstyle -T ':omz:alpha:lib:git' async-prompt }; then
+# Use async version if setting is enabled or undefined
+if zstyle -T ':omz:alpha:lib:git' async-prompt; then
   function git_prompt_info() {
-    setopt localoptions noksharrays
-    if [[ -n "$_OMZ_ASYNC_OUTPUT[_omz_git_prompt_info]" ]]; then
-      echo -n "$_OMZ_ASYNC_OUTPUT[_omz_git_prompt_info]"
+    if [[ -n "${_OMZ_ASYNC_OUTPUT[_omz_git_prompt_info]}" ]]; then
+      echo -n "${_OMZ_ASYNC_OUTPUT[_omz_git_prompt_info]}"
     fi
   }
 
   function git_prompt_status() {
-    setopt localoptions noksharrays
-    if [[ -n "$_OMZ_ASYNC_OUTPUT[_omz_git_prompt_status]" ]]; then
-      echo -n "$_OMZ_ASYNC_OUTPUT[_omz_git_prompt_status]"
+    if [[ -n "${_OMZ_ASYNC_OUTPUT[_omz_git_prompt_status]}" ]]; then
+      echo -n "${_OMZ_ASYNC_OUTPUT[_omz_git_prompt_status]}"
     fi
   }