removed 2000 x 7 ad unit

changed 

from Sohana: 
Hope you’re doing well. I met with Jim today to walk through some logic around which creative sizes should be included for the bucketing of Medium (Audio, Video, Display). He agreed with all of the logic you are currently using, minus the 200x7 creative size. This is used for Pandora One Trial Videos and he doesn’t think this should get included in the overall Display bucket. Its not a significant volume of impressions (and so shouldn’t really impact #s much), but I want to make sure our report logic is aligned. Is there a reason you'd like to keep the 2000x7 creative size as part of Display? If not, would you mind removing the 2000x7 creative size from the Display bucket?

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