- fix: NullPointerException when the config class of mod updated

- alter: better test code in `common/src/test`, `neoforge/src/test` and `fabric/src/test`, run `Test Minecraft Client(:fabric)` or `Test Minecraft Client(:neoforge)` for testing

common/src/test/resources/assets/modid/lang/en_us.json

@@ -0,0 +1,30 @@
+{
+  "modid.midnightconfig.title":"I am a title",
+  "modid.midnightconfig.text1":"I am a comment *u*",
+  "modid.midnightconfig.text2":"I am a centered comment (╯°□°）╯︵ ┻━┻",
+  "modid.midnightconfig.name":"I am a string!",
+  "modid.midnightconfig.name.label.tooltip":"I am a label tooltip \nWohoo!",
+  "modid.midnightconfig.name.tooltip":"I am a tooltip uwu \nI am a new line",
+  "modid.midnightconfig.fabric":"I am an int",
+  "modid.midnightconfig.world":"I am a double",
+  "modid.midnightconfig.showInfo":"I am a boolean",
+  "modid.midnightconfig.hello":"I am a limited int!",
+  "modid.midnightconfig.id":"I am an Item Identifier!",
+  "modid.midnightconfig.modPlatform":"I am an enum!",
+  "modid.midnightconfig.enum.ModPlatform.FORGE":"Forge",
+  "modid.midnightconfig.enum.ModPlatform.FABRIC":"Fabric",
+  "modid.midnightconfig.enum.ModPlatform.QUILT":"Quilt",
+  "modid.midnightconfig.enum.ModPlatform.NEOFORGE":"NeoForge",
+  "modid.midnightconfig.enum.ModPlatform.VANILLA":"Vanilla",
+  "modid.midnightconfig.graphicsSteps":"I am an enum with TranslatableOption!",
+  "modid.midnightconfig.myFileOrDirectory.fileChooser": "Select an image or directory",
+  "modid.midnightconfig.myFileOrDirectory.fileFilter": "Supported Images (.png, .jpg, .jpeg)",
+  "modid.midnightconfig.category.numbers": "Numbers",
+  "modid.midnightconfig.category.text": "Text",
+  "modid.midnightconfig.category.sliders": "Sliders",
+  "modid.midnightconfig.category.lists": "Lists",
+  "modid.midnightconfig.category.files": "Files",
+  "modid.midnightconfig.category.conditions": "Quiz",
+  "modid.midnightconfig.category.extras": "Extras",
+  "modid.midnightconfig.category.multiConditions": "Multi-Conditions"
+}