Fix research xp generation

docs/gyms/tiny_sword/research/gold_mine_research.tres

@@ -5,14 +5,9 @@
 
 [resource]
 script = ExtResource("1_yn72k")
-id = &"gold_research"
+id = &"gold_mine_research"
 generator_id = &"goldmine"
 name = "Gold Mine Research"
 description = "Research that improves gold mine production"
 icon = ExtResource("1_2tci1")
-xp_per_currency_produced = 0.01
-base_xp_required = 100.0
-xp_growth_multiplier = 1.5
-base_multiplier = 1.0
-multiplier_per_level = 0.1
 metadata/_custom_type_script = "uid://m7baywrfnpn0"