fix: memory leak caused by timer that never quit

[monkeyDluffy6017]

Description

The etcd related pr imported a timer that never quits.
According to the official recommendation, the timer will cause memory leak.

It will affect all versions between 3.4.0 and 3.7.0, including 3.2.2

Fixes #10392 #10349

steps to reproduce

Frequent configuration changes can cause memory to keep going up.

The memory goes from 0.2% to 1.7% in few hours

And the memory keeps stable after fixed

Checklist

• I have explained the need for this PR and the problem it solves
• I have explained the changes or the new features added to this PR
• I have added tests corresponding to this change
• I have updated the documentation to reflect this change
• I have verified that this change is backward compatible (If not, please discuss on the APISIX mailing list first)

[Virgil-Zhou]

May I ask when the updated version will be fixed? I don't want to roll back the version.

[monkeyDluffy6017]

@Virgil-Zhou No plan right now, maybe you could pick it yourself?