refactor(telemetry): enhance flushToClearcut method with retry logic and early return for empty events (#1601)

Co-authored-by: Scott Densmore <scottdensmore@mac.com>

packages/core/src/utils/retry.test.ts

@@ -6,14 +6,9 @@
 
 /* eslint-disable @typescript-eslint/no-explicit-any */
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
-import { retryWithBackoff } from './retry.js';
+import { retryWithBackoff, HttpError } from './retry.js';
 import { setSimulate429 } from './testUtils.js';
 
-// Define an interface for the error with a status property
-interface HttpError extends Error {
-  status?: number;
-}
-
 // Helper to create a mock function that fails a certain number of times
 const createFailingFunction = (
   failures: number,