fix: Correct test assertions for MessageRole and FrameEngine #11

Job	Run time
Security Audit	1m 0s
Format	15s
Clippy	46s
Test (macos-latest)	9m 1s
Test (blacksmith-4vcpu-windows-2025)	2m 31s
Build Check (blacksmith-4vcpu-windows-2025)	56s
Build Check (ubuntu-latest)	1m 2s
Build Check (macos-latest)	54s
Test (ubuntu-latest)	8m 33s
	24m 58s

Provide feedback