ALTTP: remove excess Blue Mail items from (non-progressive) hard item pool

[el-u]

What is this fixing or adding?

https://discord.com/channels/731205301247803413/1133934296122544200/1133934296122544200
With the specific setting combination of non-progressive armors plus hard item pool, a total of 4 "Blue Mail" items are placed in the multiworld.
Appropriate for this mode would be to have just 2 armor items in the pool.

How was this tested?

Generating a game with the minimal reproducible yaml

name: YourName{number}
game: A Link to the Past
A Link to the Past:
  progressive: off
  item_pool: hard

Before: 4x Blue Mail in the generated game
After: 2x Blue Mail in the generated game (+2 additional rupee items were generated)