Introduce MorphPolygonShape and CornerBasedShape polygon converters

Adds MorphPolygonShape in Compose Foundation backed by graphics-shapes Morph, enabling continuous, allocation-free morphing between PolygonShape instances across layout sizes as progress moves from 0 to 1.

- Adds MorphPolygonShape taking start and end PolygonShapes and a progress lambda.
- Adds toPolygonShape extension functions for RoundedCornerShape, CutCornerShape, and their absolute variants to allow morphing with standard corner shapes.

Test: MorphPolygonShapeTest.kt
Relnote: "Introduces `MorphPolygonShape` in Compose Foundation for morphing animations between polygon shapes, along with `toPolygonShape()` converters for `RoundedCornerShape` and `CutCornerShape`."
Fixes: 378826438
Change-Id: Ic5a8981b6bf62a67e8b191bfb6c011b50b476464