bug: when delete a route , it will trigger an exception

[jobop]

Current Behavior

When a key is deleted,and the key versions is compacted ,it will occur this exception

2022/12/01 00:02:57 [error] 306#306: *13511386 [lua] config_etcd.lua:595: failed to fetch data from etcd: /usr/local/apisix/apisix/core/config_util.lua:99: attempt to index local 'item' (a boolean value)
stack traceback:
/usr/local/apisix/apisix/core/config_util.lua:99: in function 'fire_all_clean_handlers'
/usr/local/apisix/apisix/core/config_etcd.lua:318: in function 'sync_data'
/usr/local/apisix/apisix/core/config_etcd.lua:548: in function </usr/local/apisix/apisix/core/config_etcd.lua:538>
[C]: in function 'xpcall'
/usr/local/apisix/apisix/core/config_etcd.lua:538: in function </usr/local/apisix/apisix/core/config_etcd.lua:516>, etcd key: /apisix/routes, context: ngx.timer

Expected Behavior

No response

Error Logs

No response

Steps to Reproduce

1、Turn on the etcd auto compact optim
2、Remove a route
3、Wait uitl the compacting mechanism is triggered

Environment

• APISIX version (run apisix version):3.0.0
• Operating system (run uname -a):
• OpenResty / Nginx version (run openresty -V or nginx -V):
• etcd version, if relevant (run curl http://127.0.0.1:9090/v1/server_info):3.4.16
• APISIX Dashboard version, if relevant:
• Plugin runner version, for issues related to plugin runners:
• LuaRocks version, for installation issues (run luarocks --version):