check-flagged-apis: suppress unused variable warning

Bug: 334870672
Test: m check-flagged-apis # verify no Lint warnings
Change-Id: If4fb93703f0f0bf3f27e6ec052cf488796bd717e
diff --git a/tools/check-flagged-apis/src/com/android/checkflaggedapis/Main.kt b/tools/check-flagged-apis/src/com/android/checkflaggedapis/Main.kt
index e15e7fa..e8b1b65 100644
--- a/tools/check-flagged-apis/src/com/android/checkflaggedapis/Main.kt
+++ b/tools/check-flagged-apis/src/com/android/checkflaggedapis/Main.kt
@@ -276,7 +276,7 @@
     if (methodSignatureParts.size != 3) {
       throw Exception("Bad XML: method signature '$methodSignature'")
     }
-    var (methodName, methodArgs, methodReturnValue) = methodSignatureParts
+    var (methodName, methodArgs, _) = methodSignatureParts
     val packageAndClassName =
         requireNotNull(method.getParentNode()?.getAttribute("name")) {
           "Bad XML: top level <method> element, or <class> element missing name attribute"