[evals] `inject_context` might not be needed

[jiahaog]

Referring to

A2UI/eval/a2ui_eval/solvers.py

Lines 95 to 106 in ade478f

	def inject_context() -> Solver:
	"""Solver that injects evaluation context into the user prompt."""
	async def solve(state: TaskState, generate: Generate) -> TaskState:
	context = state.metadata.get('context')
	if context:
	for msg in state.messages:
	if msg.role == "user":
	msg.content = f"Context:\n{context}\n\n{msg.content}"
	break
	return state
	return solve

This seems to be only used for one eval - See contextAwareUI in the decrypted eval/datasets/v0_9_prompts.yaml.

I think we can get away with dropping this custom solver, and just inlining the context string in the promptText?

cc @gspencergoog