Extended Part A of Master Spool Prusa Mini Edition

Since I had a problem with fitting the Fiberlogy's refill filament on the original “Master Spool Prusa Mini Edition”, I've remixed the “Part A” of the spool by adding additional 11mm of height to the core. In total, the assembled spool should have ~65mm of width, which was close enough for my needs (and nearly matches the Prusament's spool width, in my case measured as 67mm).