chore: Remove old FIXME

[zlangley]

From ininitial implementation of verifier that did not handle RAP phases

[github-actions]

group	app.proof_time_ms	app.cycles	app.cells_used	leaf.proof_time_ms	leaf.cycles	leaf.cells_used
verify_fibair	(-18 [-0.5%]) 3,786	746,376	30,012,414	-	-	-
fibonacci_program	(-42 [-0.7%]) 6,063	1,500,137	51,505,102	-	-	-
regex_program	(+336 [+1.8%]) 18,793	4,190,904	165,028,173	-	-	-
ecrecover_program	(-23 [-0.9%]) 2,593	285,401	15,092,297	-	-	-

Commit: bc65cd8

Benchmark Workflow