fix: configure ForgeGradle 5.2.5 via buildscript block

- Add buildscript block to forge/build.gradle with Forge maven repo
- Remove net.minecraftforge.gradle from settings.gradle pluginManagement
- ForgeGradle 5.2.5 uses legacy buildscript resolution, not pluginManagement

Author: Meeuyt

forge/build.gradle

@@ -1,3 +1,17 @@
+buildscript {
+    repositories {
+        maven {
+            name = "Forge"
+            url = uri("https://maven.minecraftforge.net")
+        }
+        gradlePluginPortal()
+        mavenCentral()
+    }
+    dependencies {
+        classpath "net.minecraftforge.gradle:ForgeGradle:5.2.5"
+    }
+}
+
 plugins {
     id 'multiloader-loader'
     id 'net.minecraftforge.gradle' version '5.2.5'

settings.gradle

@@ -32,7 +32,6 @@ pluginManagement {
     }
     plugins {
         id "org.jetbrains.kotlin.kapt" version '2.2.0'
-        id "net.minecraftforge.gradle" version "6.0.24"
     }
 }