Update ECE troubleshooting docs (#4213)

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This is from an [internal discussion
here](https://elastic.slack.com/archives/CKJ209XJL/p1764836058110659?thread_ts=1764835256.713879&cid=CKJ209XJL).

First, we have a troubleshooting doc:

https://www.elastic.co/docs/troubleshoot/deployments/cloud-enterprise/common-issues
> Symptom: You have no access to API and UI because all coordinators are
lost. More than half of the director hosts are available. If you have 5
directors, 3 directors must be available. If you lost more than half of
the directors, contact the support. If all directors are lost,
[re-install
ECE](https://www.elastic.co/docs/deploy-manage/deploy/cloud-enterprise/install).

It's confusing for `if you lost more than half of the directors, contact
the support.`, because "only contact support" causes over-expectation
that support can fix, but the actual fact is not that straightforward.

We discuss internally that, we want to make it more clear what users
could do when they observe more than half of the directors (where
zookeeper nodes running on) are lost, and thus caused the zookeeper
quorum broken.

In this situation, we have a doc below talking about users can gather
essential information and we can help them investigate, if there's still
a possibility to recover the Zookeeper leader or not. (It depends on the
status and this recovery is not guaranteed.) We concluded that we could
simply link below doc to above troubleshooting doc.


https://www.elastic.co/docs/troubleshoot/deployments/cloud-enterprise/rebuilding-broken-zookeeper-quorum#ece_determine_the_zookeeper_leader

### Preview before merge


[troubleshoot/deployments/cloud-enterprise/common-issues.md](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/4213/troubleshoot/deployments/cloud-enterprise/common-issues)

### View after merge


https://www.elastic.co/docs/troubleshoot/deployments/cloud-enterprise/common-issues

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---

Thank you!

cc @fdartayre @R0ky

---------

Co-authored-by: David Kilfoyle <41695641+kilfoyle@users.noreply.github.com>

Author: kunisen

troubleshoot/deployments/cloud-enterprise/common-issues.md

@@ -17,7 +17,7 @@ This set of common symptoms and resolutions can help you to diagnose unexpected
 
 ## Emergency token not spinning up the coordinator role [ece_emergency_token_not_spinning_up_the_coordinator_role]
 
-**Symptom:** You have no access to API and UI because all coordinators are lost. More than half of the director hosts are available. If you have 5 directors, 3 directors must be available. If you lost more than half of the directors, contact the support. If all directors are lost, [re-install ECE](../../../deploy-manage/deploy/cloud-enterprise/install.md).
+**Symptom:** You have no access to API and UI because all coordinators are lost. More than half of the director hosts are available. If you have 5 directors, 3 directors must be available. If more than half of the directors are lost, it is crucial to investigate whether the ZooKeeper quorum can recover. Please refer to [Determine the Zookeeper leader](../cloud-enterprise/rebuilding-broken-zookeeper-quorum.md#ece_determine_the_zookeeper_leader) to gather essential information, and then contact support for further assistance. If all directors are lost, [re-install ECE](../../../deploy-manage/deploy/cloud-enterprise/install.md).
 
 **Resolution:** Use the emergency token provided during the installation of the genesis ECE nodes. You must explicitly specify the roles with the parameter `--roles`, for example `"coordinator,director,proxy"`. Otherwise, the host does not run any role.