Fix JavaSourceSet#gavFromPath for TypeTable jar layout

After #7528 TypeTable materializes artifacts as jar files inside the
version directory rather than as a classes directory. The .tt branch
in gavFromPath used fixed offsets that worked for the legacy directory
layout but mis-sliced GAV components for the new jar layout.

Compute versionIndex/artifactIndex off the tail and shift left by one
when the trailing path component ends with .jar, so the slice points
at the right components in either layout.

Author: steve-aom-elliott

rewrite-java/src/main/java/org/openrewrite/java/marker/JavaSourceSet.java

@@ -471,10 +471,15 @@ public static JavaSourceSet build(String sourceSetName, Collection<Path> classpa
                 version = pathParts.get(pathParts.size() - 3);
             } else if (pathParts.contains(".tt")) {
                 int ttIndex = pathParts.indexOf(".tt");
-                if (pathParts.size() - ttIndex > 3) {
-                    groupId = String.join(".", pathParts.subList(ttIndex + 1, pathParts.size() - 2));
-                    artifactId = pathParts.get(pathParts.size() - 2);
-                    version = pathParts.get(pathParts.size() - 1);
+                int last = pathParts.size() - 1;
+                // Legacy layout ends at the version directory; post-#7528 layout adds
+                // a trailing <artifact>-<version>.jar file inside the version directory.
+                int versionIndex = pathParts.get(last).endsWith(".jar") ? last - 1 : last;
+                int artifactIndex = versionIndex - 1;
+                if (artifactIndex - (ttIndex + 1) >= 1) {
+                    groupId = String.join(".", pathParts.subList(ttIndex + 1, artifactIndex));
+                    artifactId = pathParts.get(artifactIndex);
+                    version = pathParts.get(versionIndex);
                 }
             } else if (pathParts.size() >= 4) {
                 version = pathParts.get(pathParts.size() - 2);