fix: Fixes managed resources missing from the JAR

**Problem**
RC-7 is missing the managed resources.

**Solution**
This triggers managed resources so they get generated.

main/src/main/scala/sbt/Defaults.scala

@@ -4084,6 +4084,7 @@ object Classpaths {
     val resourceDirs = resourceDirectories.value
     val vfBackendDir = compileIncremental.value._2
     val backendDir = c.toPath(vfBackendDir)
+    val _ = resources.value
     backendDir.toFile() :: resourceDirs.toList.filter(_.exists())
   }
 

sbt-app/src/sbt-test/plugins/auto-plugins-minimal/a/src/main/scala/A.scala

@@ -0,0 +1,3 @@
+import sbt.*
+
+object A extends AutoPlugin

sbt-app/src/sbt-test/plugins/auto-plugins-minimal/build.sbt

@@ -0,0 +1,23 @@
+scalaVersion := "3.7.4"
+
+organization := "com.example"
+
+@transient
+lazy val check = taskKey[Unit]("extract jar file")
+
+lazy val a = (project in file("a"))
+  .enablePlugins(SbtPlugin)
+  .settings(
+    name := "a",
+    check := Def.uncached {
+      val converter = fileConverter.value
+      val p = converter.toPath((Compile / packageBin).value)
+      val outDir = target.value / "extracted"
+      IO.unzip(p.toFile(), outDir)
+      val expectedResource = outDir / "sbt" / "sbt.autoplugins"
+      if !expectedResource.exists() then
+        sys.error(s"$expectedResource doesn't exist")
+      val content = IO.read(outDir / "sbt" / "sbt.autoplugins").trim
+      assert(content == "A", s"expected A, but content was '$content'")
+    },
+  )

sbt-app/src/sbt-test/plugins/auto-plugins-minimal/test

@@ -0,0 +1,2 @@
+> a/packageBin
+> a/check