Fix for KT-13695, KT-13159 J2K: Invalid conversion context setup for plain text pastes

Extending, Implementing, imports from paste target file previously not implemented

idea/testData/copyPaste/plainTextConversion/OverrideInterface.dependency.java

@@ -0,0 +1,7 @@
+package test;
+
+import org.jetbrains.annotations.Nullable;
+
+public interface JavaInterface {
+    void subject(@Nullable String s)
+}