STCC-329/330/331 Fixed bugs in conversion [TN]

[TauBossss]

There were some bugs in the conversion of the next backdrop and change backdrop brick. The next backdrop wasnt working at all, it just converted to a next look in the sprite. The change backdrop converted to a workaround, if the backdrop name contained the word "backdrop". And random did not work at all because the block that was created did not exist anymore.

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