Actually have a chance to reuse optional property signatures in the node builder (microsoft#57995)

Author: weswigham

src/compiler/checker.ts

@@ -8551,7 +8551,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             if (typeFromTypeNode === type) {
                 return true;
             }
-            if (annotatedDeclaration && (isParameter(annotatedDeclaration) || isPropertyDeclaration(annotatedDeclaration)) && annotatedDeclaration.questionToken) {
+            if (annotatedDeclaration && (isParameter(annotatedDeclaration) || isPropertySignature(annotatedDeclaration) || isPropertyDeclaration(annotatedDeclaration)) && annotatedDeclaration.questionToken) {
                 return getTypeWithFacts(type, TypeFacts.NEUndefined) === typeFromTypeNode;
             }
             return false;

tests/baselines/reference/avoidNarrowingUsingConstVariableFromBindingElementWithLiteralInitializer.types

@@ -8,8 +8,8 @@ declare const foo: ["a", string, number] | ["b", string, boolean];
 export function test(arg: { index?: number }) {
 >test : (arg: { index?: number; }) => void
 >     : ^^^^^^                   ^^^^^^^^^
->arg : { index?: number | undefined; }
->    : ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+>arg : { index?: number; }
+>    : ^^^^^^^^^^      ^^^
 >index : number | undefined
 >      : ^^^^^^^^^^^^^^^^^^