Drop potentially too-long-for-MySQL index altcha fields that we don't

need any more

db/migrate/20250609210440_create_altcha_solutions.rb

@@ -9,7 +9,5 @@ class CreateAltchaSolutions < ActiveRecord::Migration[8.0]
 
       t.timestamps
     end
-
-    add_index :altcha_solutions, [:algorithm, :challenge, :salt, :signature, :number], unique: true, name: "index_altcha_solutions"
   end
 end

db/migrate/20260604160600_drop_altcha_solutions.rb

@@ -13,10 +13,5 @@ class DropAltchaSolutions < ActiveRecord::Migration[8.0]
 
       t.timestamps
     end
-
-    add_index :altcha_solutions,
-      [:algorithm, :challenge, :salt, :signature, :number],
-      unique: true,
-      name: "index_altcha_solutions"
   end
 end