No, a felony conspiracy conviction would not disqualify you for the American Opportunity Tax Credit.
Publication 970 Tax Benefits for Education defines "felony drug conviction" as a "felony for possessing or distributing a controlled substance" (Table 2-1, Page 11).
"Conspiracy" and "possession/distribution? are two distinct crimes. You can conspire to "possess or distribute a controlled substance", without ever doing so. You can also be convicted of conspiracy to commit a crime without committing the crime itself.
