bug: we don't need to stop parsing nested dirs if `maven-metadata.xml` file is found

## Description
There are times when a directory uses different GroupIDs.
In these cases first dir with `maven-metadata.xml` file will contain not only version dirs, but also dirs for other artifacts.

e.g.:
- https://repo1.maven.org/maven2/org/eclipse/jdt/core/maven-metadata.xml
- https://repo1.maven.org/maven2/org/eclipse/jdt/core/compiler/ecj/maven-metadata.xml
- https://repo1.maven.org/maven2/org/eclipse/jdt/core/manipulation/maven-metadata.xml

Start by tracing the nested-directory parser using the Maven repository examples in the issue, especially the org/eclipse/jdt/core path and its child paths. Verify how discovering maven-metadata.xml affects traversal, then confirm that version directories and other artifact directories are both examined without prematurely stopping.

Written by the indexing model from the issue text.