Purge versions of previously deleted content doesn't work since 5.5

Since MAGNOLIA-6774 introduces new path's structure of version in magnolia-mgnlVersion workspace so info.magnolia.tools.commands.VersionStorePurgeCommand#purge has never reached (https://git.magnolia-cms.com/projects/ENTERPRISE/repos/tools/browse/src/main/java/info/magnolia/tools/commands/VersionStorePurgeCommand.java#110).

Reason is mgnlVersion.getRootNode().getNodes() only get child of root node from magnolia-mgnlVersion workspace and those nodes alway invalid because of missing mix:versionable.
More code details:

• https://git.magnolia-cms.com/projects/ENTERPRISE/repos/tools/browse/src/main/java/info/magnolia/tools/commands/VersionStorePurgeCommand.java#92
• https://git.magnolia-cms.com/projects/ENTERPRISE/repos/tools/browse/src/main/java/info/magnolia/tools/commands/VersionStorePurgeCommand.java#102
• https://git.magnolia-cms.com/projects/ENTERPRISE/repos/tools/browse/src/main/java/info/magnolia/tools/commands/VersionStorePurgeCommand.java#166

Step to reproduce:

• Create page with name 'test' in pages app
• Publish that 'test' page
• Check version of it is created in JCR-Browser app/magnolia-mgnlVersion
• Open Groovy app
• Run below script to delete 'test' page, note: the name of page (in my case 'test') need to change if you create a different name

java.lang.String querySql2 = "select * from [mgnl:page] as t where name(t) = 'test'";
java.lang.String queryWorkspace = "website";
 
javax.jcr.NodeIterator nodeList = info.magnolia.cms.util.QueryUtil.search(queryWorkspace, querySql2, javax.jcr.query.Query.JCR_SQL2, "mgnl:page");
 
println "Removing nodes :";
while(nodeList.hasNext()) {
  javax.jcr.Node currNode = nodeList.nextNode();
  println "${currNode.path}";
  currNode.remove();
}
 
info.magnolia.context.MgnlContext.getJCRSession(queryWorkspace).save();
println "Nodes removal finished";

• Check the 'test' page is gone in Pages app
• Open JCR-Browser app/magnolia-mgnlVersion and make sure that the all node related to version of 'test' from step 3 is still existed
• Open Repository tools app and click purge version in magnolia-mgnlVersion
• Open JCR-Browser app/magnolia-mgnlVersion again and check the node has mix:versionable or node name is uuid

Expectation: Version of 'test' page is gone
Observation: Version of 'test' page still exist