Use warn mode by default for jspecify nullability annotations in 1.6

^KT-48851 Fixed

compiler/testData/diagnostics/foreignAnnotationsTests/java8Tests/jspecify/default.fir.kt

@@ -0,0 +1,29 @@
+// FILE: NullnessUnspecifiedTypeParameter.java
+import org.jspecify.nullness.*;
+
+@NullMarked
+public class NullnessUnspecifiedTypeParameter<T> {
+    public void foo(T t) {}
+
+    public void bar(Test s, T t) {} // t should not become not nullable
+}
+
+// FILE: Test.java
+public class Test {}
+
+// FILE: main.kt
+fun main(a1: NullnessUnspecifiedTypeParameter<Any>, a2: NullnessUnspecifiedTypeParameter<Any?>, x: Test): Unit {
+    a1.foo(null)
+    a1.foo(1)
+
+    a2.foo(null)
+    a2.foo(1)
+
+    a1.bar(null, null)
+    a1.bar(x, null)
+    a1.bar(x, 1)
+
+    a2.bar(null, null)
+    a2.bar(x, null)
+    a2.bar(x, 1)
+}