Updates the container colors for incoming and outgoing message bubbles to align with Material 3 design tokens.
- The outgoing message bubble container color is changed from `surfaceColorAtElevation(2.dp)` to `surfaceContainer`.
- The reply container color within an outgoing message is changed from `primaryContainer` to `surfaceContainerHighest`.
Additionally, the `@Preview` for `MessageBubble` is updated to display both an incoming and an outgoing message for better design validation.
melod1n
389d3f9e52