Missing keystore step in the upgrade guide

[juliamagan]

Description

During testing at wazuh/wazuh#23062, it has been found that when updating, configuration steps are missing for Vulnerability Detection to work properly. It is indeed advised to follow the user manual in order to configure the new capabilities. However, although the new indexer configuration is specified, the wazuh-keystore commands are not added:

In the step-by-step installation we can see that this command is optional if you are not going to use Vulnerability Detection:

However, suppose we follow the upgrade guide, and go to the user manual where it redirects us, accessing the Vulnerability Detection configuration section. In that case, we do not see anything about these commands, so the user will not be able to correctly configure the environment after the upgrade.

[Dwordcito]

@ncvicchi take a look on this.