fix(language-service): [Ivy] hybrid visitor should not locate let keyword (#39061)

Fixed a boolean logic error that prevented hybrid visitor from returning
undefined when a variable does not have value and cursor is not in the
key span.

PR Close #39061

packages/language-service/ivy/hybrid_visitor.ts

@@ -27,9 +27,11 @@ export function findNodeAtPosition(ast: t.Node[], position: number): t.Node|e.AS
   }
   if (isTemplateNodeWithKeyAndValue(candidate)) {
     const {keySpan, valueSpan} = candidate;
+    const isWithinKeyValue =
+        isWithin(position, keySpan) || (valueSpan && isWithin(position, valueSpan));
+    if (!isWithinKeyValue) {
       // If cursor is within source span but not within key span or value span,
       // do not return the node.
-    if (!isWithin(position, keySpan) && (valueSpan && !isWithin(position, valueSpan))) {
       return;
     }
   }

packages/language-service/ivy/test/hybrid_visitor_spec.ts

@@ -504,8 +504,7 @@ describe('findNodeAtPosition for microsyntax expression', () => {
     const {errors, nodes, position} = parse(`<div *ngFor="l¦et item of items"></div>`);
     expect(errors).toBe(null);
     const node = findNodeAtPosition(nodes, position);
-    // TODO: this is currently wrong because node is currently pointing to
-    // "item". In this case, it should return undefined.
+    expect(node).toBeUndefined();
   });
 
   it('should locate let variable', () => {