Documentation should be updated to not mention elytron-tool.jar usage

It is mentioned here  https://docs.wildfly.org/27/WildFly_Elytron_Security.html#Security_Vault_Migration that we can use elytron-tool.jar instead of the elytron-tool.sh script. This does not work anymore because the elytron-tool is no longer a shaded jar, see ELY-2251 and WFCORE-5712 . This issue is to update the docs to remove the mention of $JBOSS_HOME/bin/wildfly-elytron-tool.jar usage.