[JS] Forbid export of interfaces

With the only exception of external interfaces.

See https://youtrack.jetbrains.com/issue/KT-44099

compiler/testData/diagnostics/testsWithJsStdLib/export/extendingNonExportedType.kt

@@ -20,7 +20,7 @@ open class ExportedGenericClass<T>
 class <!NON_EXPORTABLE_TYPE("super; ExportedGenericClass<NonExportedClass>")!>ExportedClass3<!> : ExportedGenericClass<NonExportedClass>()
 
 @JsExport
-interface ExportedGenericInterface<T>
+interface <!WRONG_EXPORTED_DECLARATION!>ExportedGenericInterface<!><T>
 
 @JsExport
 class <!NON_EXPORTABLE_TYPE("super; ExportedGenericInterface<NonExportedClass>")!>ExportedClass4<!> : ExportedGenericInterface<NonExportedClass>

compiler/testData/diagnostics/testsWithJsStdLib/export/unexportableTypesInTypeParameters.kt

@@ -14,4 +14,4 @@ fun <<!NON_EXPORTABLE_TYPE("upper bound; C")!>T : C<!>>foo() { }
 class A<<!NON_EXPORTABLE_TYPE("upper bound; C")!>T : C<!>, <!NON_EXPORTABLE_TYPE("upper bound; I")!>S: I<!>>
 
 @JsExport
-interface I2<<!NON_EXPORTABLE_TYPE("upper bound; C"), NON_EXPORTABLE_TYPE("upper bound; I")!>T<!>> where T : C, T : I
+interface <!WRONG_EXPORTED_DECLARATION!>I2<!><<!NON_EXPORTABLE_TYPE("upper bound; C"), NON_EXPORTABLE_TYPE("upper bound; I")!>T<!>> where T : C, T : I

compiler/testData/diagnostics/testsWithJsStdLib/export/wrongExportedDeclaration.kt

@@ -18,3 +18,9 @@ enum class <!WRONG_EXPORTED_DECLARATION("enum class")!>EnumClass<!> { ENTRY1, EN
 
 @JsExport
 annotation class <!WRONG_EXPORTED_DECLARATION("annotation class")!>AnnotationClass<!>
+
+@JsExport
+interface <!WRONG_EXPORTED_DECLARATION("interface")!>SomeInterface<!>
+
+@JsExport
+external interface GoodInterface

compiler/testData/diagnostics/testsWithJsStdLib/export/wrongExportedDeclaration.txt

@@ -30,4 +30,16 @@ package foo {
         public final /*synthesized*/ fun valueOf(/*0*/ value: kotlin.String): foo.EnumClass
         public final /*synthesized*/ fun values(): kotlin.Array<foo.EnumClass>
     }
+
+    @kotlin.js.JsExport public external interface GoodInterface {
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
+
+    @kotlin.js.JsExport public interface SomeInterface {
+        public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    }
 }