chore(docs): Remove npm reference section from testing page (AztecProtocol#3719)

This PR removes a reference to using aztec-sandbox in typescript tests.

# Checklist:
Remove the checklist to signal you've completed it. Enable auto-merge if
the PR is ready to merge.
- [ ] If the pull request requires a cryptography review (e.g.
cryptographic algorithm implementations) I have added the 'crypto' tag.
- [ ] I have reviewed my diff in github, line by line and removed
unexpected formatting changes, testing logs, or commented-out code.
- [ ] Every change is related to the PR description.
- [ ] I have
[linked](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue)
this pull request to relevant issues (if any exist).

Author: critesjosh

docs/docs/dev_docs/tutorials/testing.md

@@ -80,16 +80,6 @@ Instead of creating new accounts in our test suite, we can use the ones already
 
 #include_code use-existing-wallets /yarn-project/end-to-end/src/guides/dapp_testing.test.ts typescript
 
-### Running Sandbox in the nodejs process
-
-Instead of connecting to a local running Sandbox instance, you can also start your own Sandbox within the nodejs process running your tests, for an easier setup. To do this, import the `@aztec/aztec-sandbox` package in your project, and run `createSandbox` during setup. Note that this will still require you to run a local Ethereum development node like [Anvil](https://book.getfoundry.sh/anvil/), [Hardhat Network](https://hardhat.org/hardhat-network/docs/overview), or [Ganache](https://trufflesuite.com/ganache/).
-
-#include_code in-proc-sandbox /yarn-project/end-to-end/src/guides/dapp_testing.test.ts typescript
-
-The `createSandbox` returns a `stop` callback that you should run once your test suite is over to stop all Sandbox services.
-
-#include_code stop-in-proc-sandbox /yarn-project/end-to-end/src/guides/dapp_testing.test.ts typescript
-
 ## Assertions
 
 We will now see how to use `aztec.js` to write assertions about transaction statuses, about chain state both public and private, and about logs.