SDK: Fix process not defined error in Vite (#8280)

<!--

## title your PR with this format: "[SDK/Dashboard/Portal] Feature/Fix: Concise title for the changes"

If you did not copy the branch name from Linear, paste the issue tag here (format is TEAM-0000):

## Notes for the reviewer

Anything important to call out? Be sure to also clarify these in your comments.

## How to test

Unit tests, playground, etc.

-->

<!-- start pr-codex -->

---

## PR-Codex overview

This PR addresses a `process not defined` error that occurs when using the `thirdweb/contract` import in Vite by ensuring that the `process` variable is only accessed when it is defined.

### Detailed summary

- Updated `PUBLISHED_PRIVATE_KEY` export in `packages/thirdweb/src/utils/any-evm/zksync/constants.ts` to check if `process` is defined before accessing `process.env.ZKSYNC_PUBLISHED_PRIVATE_KEY`.

> ✨ Ask PR-Codex anything about this PR by commenting with `/codex {your question}`

<!-- end pr-codex -->

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **Chores**
  - Improved robustness of environment configuration handling to avoid runtime issues in non-Node environments.

- **Bug Fixes**
  - Fixed a "process not defined" error that could occur when importing the library in Vite, included in a patch release.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: MananTank

.changeset/small-taxes-heal.md

@@ -0,0 +1,5 @@
+---
+"thirdweb": patch
+---
+
+Fix process not defined error when using "thirdweb/contract" import in Vite

packages/thirdweb/src/utils/any-evm/zksync/constants.ts

@@ -3,9 +3,10 @@ export const ZKSYNC_SINGLETON_FACTORY =
 export const CONTRACT_DEPLOYER_ADDRESS =
   "0x0000000000000000000000000000000000008006" as const;
 export const KNOWN_CODES_STORAGE = "0x0000000000000000000000000000000000008004";
-export const PUBLISHED_PRIVATE_KEY = process
-  ? process.env.ZKSYNC_PUBLISHED_PRIVATE_KEY
-  : undefined;
+export const PUBLISHED_PRIVATE_KEY =
+  typeof process !== "undefined" && process && process.env
+    ? process.env.ZKSYNC_PUBLISHED_PRIVATE_KEY
+    : undefined;
 
 export const singletonFactoryAbi = [
   "function deploy(bytes32,bytes32,bytes) external payable",