…che#11399) (apache#11400)

When using flatten-maven-plugin with updatePomFile=true and parent expansion,
Maven incorrectly detected a parent cycle during the install phase. The error
occurred because the consumer POM builder was using Path instead of ModelSource
when reading the flattened POM.

This change updates the PomArtifactTransformer API to use ModelSource instead
of Path. ModelSource includes the necessary context (base directory, ModelLocator)
to properly resolve parent POMs and avoid false cycle detection.

Changes:
- Updated PomArtifactTransformer.transform() to accept ModelSource instead of Path
- Modified ConsumerPomArtifactTransformer to create ModelSource with proper resolution context
- Updated DefaultConsumerPomBuilder and related classes to work with ModelSource
- Added integration test to verify the fix

Fixes apache#11399

(cherry picked from commit 5ec059c)

# Conflicts:
#	impl/maven-core/src/test/java/org/apache/maven/internal/transformation/impl/ConsumerPomArtifactTransformerTest.java