build(deps-dev): update @types/sinon to 21.0.1 and fix fake timer test leaks

Author: lahirumaramba

package-lock.json

@@ -247,7 +247,7 @@
     "@types/node": "^25.7.0",
     "@types/request": "^2.47.0",
     "@types/request-promise": "^4.1.41",
-    "@types/sinon": "^17.0.2",
+    "@types/sinon": "^21.0.1",
     "@types/sinon-chai": "^3.0.0",
     "@types/uuid": "^10.0.0",
     "@typescript-eslint/eslint-plugin": "^8.59.3",

package.json

@@ -1101,7 +1101,9 @@ describe('HttpClient', () => {
   });
 
   it('should wait when retry-after expressed as a timestamp', () => {
-    clock = sinon.useFakeTimers();
+    clock = sinon.useFakeTimers({
+      toFake: ['Date', 'setTimeout', 'clearTimeout', 'setInterval', 'clearInterval']
+    });
     clock.setSystemTime(1000);
     const timestamp = new Date(clock.now + 30 * 1000);
 

test/unit/utils/api-request.spec.ts

@@ -599,7 +599,10 @@ describe('UrlKeyFetcher', () => {
       mockedRequests.push(mockFetchPublicKeys());
       mockedRequests.push(mockFetchPublicKeys());
 
-      clock = sinon.useFakeTimers(1000);
+      clock = sinon.useFakeTimers({
+        now: 1000,
+        toFake: ['Date', 'setTimeout', 'clearTimeout', 'setInterval', 'clearInterval']
+      });
 
       return keyFetcher.fetchPublicKeys().then(() => {
         expect(https.request).to.have.been.calledOnce;
@@ -716,7 +719,10 @@ describe('JwksFetcher', () => {
       mockedRequests.push(mockFetchJsonWebKeys());
       mockedRequests.push(mockFetchJsonWebKeys());
 
-      clock = sinon.useFakeTimers(1000);
+      clock = sinon.useFakeTimers({
+        now: 1000,
+        toFake: ['Date', 'setTimeout', 'clearTimeout', 'setInterval', 'clearInterval']
+      });
 
       return keyFetcher.fetchPublicKeys().then(() => {
         expect(https.request).to.have.been.calledOnce;