The previous sentence says that cases "affecting ambassadors etc." are those in which the SC has original jurisdiction. This sentence therefore cannot grant appellate jurisdiction to the same cases. That would be absurd.
Consequently, it is clear that Congress cannot limit the SC's (original) jurisdiction with regard to ambassadors, etc., and that Congrss can limit the SC's (appellate) jurisdiction with regard to "all cases, in law and equity, etc.".
That said, I think that this proposed bill is silly. Congress should not pretend that it can vote itself the power to declare that something is constitutional, and, as the earlier poster pointed out, with the same majority it could simply impeach a Supreme Court justice which it felt had rendered an outrageous decision.