Worldgen settings with empty structures parameter generates all structures extremely frequent

The bug

When setting the generator.settings.structures parameter to an empty map, I would expect no structures to spawn. Instead every possible structure spawns in their respective biome, with the default settings for spacing, separation and salt. This causes the structures to spawn extremely frequent.

The expected behavior is that either no structures spawn, or that they spawn with more sensible defaults.

Relevant section in the worldgen settings

"generator": {
  "settings": {
    "structures": {
      "structures": {}
    }
  }
}

How to reproduce

1. Download the worldgen settings frequent_structures.json
2. Create a new world and select the downloaded file when importing world settings
3. Teleport to the custom:icy dimension

   /execute in custom:icy run tp @s ~ 100 ~

   Notice that all types of structures spawn excessively and close to each other