fix: plugin_metadata not populating to the correct etcd key

[zhuoyang]

Type of change:

• Bugfix

What this PR does / why we need it:

Fix plugin_metadata_cm not working due to populating to wrong etcd key
Before this fix, this can be seen in the debug log

2023-10-18T11:31:03+08:00	[35mdebug[0m	apisix/cluster.go:1225	push event to adapter	{"event": "create", "key": "/apisix/plugin_metadatas/datadog", "value": "{\"host\":\"datadog.datadog\",\"namespace\":\"apisix\",\"port\":8125}"}

Pre-submission checklist:

• Did you explain what problem does this PR solve? Or what new features have been added?
• Have you added corresponding test cases?
• Have you modified the corresponding document?
• Is this PR backward compatible? If it is not backward compatible, please discuss on the mailing list first

[codecov-commenter]

Codecov Report

Merging #2012 (2aa0488) into master (5177b5f) will not change coverage.
Report is 5 commits behind head on master.
The diff coverage is 0.00%.

❗ Current head 2aa0488 differs from pull request most recent head b78d0d5. Consider uploading reports for the commit b78d0d5 to get more accurate results

@@           Coverage Diff           @@
##           master    #2012   +/-   ##
=======================================
  Coverage   36.81%   36.81%           
=======================================
  Files          93       93           
  Lines        7863     7863           
=======================================
  Hits         2895     2895           
  Misses       4580     4580           
  Partials      388      388           

Files	Coverage Δ
pkg/apisix/plugin_metadata.go	2.23% <0.00%> (ø)

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[lingsamuel]

It would be better to have some e2e tests for this function.

[zhuoyang]

I agree, but I will need some time as there are other priority for me right now

[indrekj]

I saw you fixed the wrong path in the helm charts. Do you think it's also worth fixing it in this repo as well: https://github.com/apache/apisix-ingress-controller/blob/master/conf/config-default.yaml#L86 (should also be on the root level)

[zhuoyang]

I am actually having a hard time understanding the e2e test, it seems like there's e2e test written for this feature already but why does it not fail in the first place?
I did pass in ENABLED_ETCD_SERVER=true when I run make e2e-test-local, tried both with and without my fix, the test still pass anyway

[zhuoyang]

thanks for merging! is it possible to release a hotfix for this PR?

[lingsamuel]

thanks for merging! is it possible to release a hotfix for this PR?

Sure. Patch version 1.7.1 is voting, thread here:

https://lists.apache.org/thread/fjy8t21nrj2yyfvrmyshlokc6w3jcgp