Add implementation of ApiFetchedDTO and fix error message

Author: mvgreen

src/main/kotlin/com/ecwid/apiclient/v3/dto/report/result/FetchedReportAdviceResponse.kt

@@ -1,5 +1,11 @@
 package com.ecwid.apiclient.v3.dto.report.result
 
+import com.ecwid.apiclient.v3.dto.common.ApiFetchedDTO
+
 data class FetchedReportAdviceResponse(
 	val tip: String? = null
-)
+) : ApiFetchedDTO {
+
+	override fun getModifyKind() = ApiFetchedDTO.ModifyKind.ReadOnly
+
+}

src/test/kotlin/com/ecwid/apiclient/v3/DtoContractUnitTest.kt

@@ -151,7 +151,7 @@ class DtoContractUnitTest {
 			.filterNot { dtoClass -> dtoClass.isClassifiedDTOOrEnclosingClass(*dtoMarkerInterfaces) }
 		assertTrue(problemDtoClasses.isEmpty()) {
 			val interfacesStr = dtoMarkerInterfaces.joinToString(separator = ", ") { int -> int.simpleName }
-			"Some of top level DTO data classes does implement one of marker interfaces [$interfacesStr]:\n" +
+			"Some of top level DTO data classes do not implement any marker interfaces [$interfacesStr]:\n" +
 				classesToLoggableString(problemDtoClasses)
 		}
 	}