Generate Ground Icicles in the Ice Spikes Biome

Now that icicles are being introduced, they would be a perfect addition to the Ice Spikes biome to make it feel more “epic” and detailed.

• These would generate on the ground of this biome, different to growing from the ceiling. (like they'll do on the newly revealed Ice Caves)
• They give players extra detail to discover in one of the rarest biomes without requiring entirely new blocks.
• They would give the landscape a sharper, colder feel, going along nicely with the massive towering spikes!