Make Blueprint steps documentRoot agnostic

Description

I've found some users setSiteOptions blueprint step on wp-now get some errors due the documentRoot being hardcoded instead of reading the value from

https://github.com/WordPress/wordpress-playground/blob/45233583e635f35c0751b5340dfa07102eabbc46/packages/playground/blueprints/src/lib/steps/site-data.ts#L37

Can we make the

Steps to reproduce

1. Create a file called blueprint.json with this content

{
		"landingPage": "/friends/",
		"steps": [
			{
				"step": "setSiteOptions",
				"options": {
					"permalink_structure": "/%year%/%monthnum%/%day%/%postname%/"
				}
			}
		]
}

2. Run npx @wp-now/wp-now start --blueprint=blueprint.json
3. See the error:

 npx @wp-now/wp-now start --blueprint=blueprint.json                                                                                                                                                                                                                                                    х INT 16m 25s Node 20.8.1 11:18:08
Starting the server......
directory: /Users/macbookpro/Downloads/downloads/friends
mode: plugin
php: 8.0
wp: latest
WordPress latest folder already exists. Skipping download.
SQLite folder already exists. Skipping download.
blueprint steps: 1
PHPResponse {
  headers: {
    'x-powered-by': [ 'PHP/8.0.10-dev' ],
    'content-type': [ 'text/html; charset=UTF-8' ]
  },
  bytes: Uint8Array(516) [
     60,  98, 114,  32,  47,  62,  10,  60,  98,  62,  87,  97,
    114, 110, 105, 110, 103,  60,  47,  98,  62,  58,  32,  32,
    105, 110,  99, 108, 117, 100, 101,  40, 119, 111, 114, 100,
    112, 114, 101, 115, 115,  47, 119, 112,  45, 108, 111,  97,
    100,  46, 112, 104, 112,  41,  58,  32,  70,  97, 105, 108,
    101, 100,  32, 116, 111,  32, 111, 112, 101, 110,  32, 115,
    116, 114, 101,  97, 109,  58,  32,  78, 111,  32, 115, 117,
     99, 104,  32, 102, 105, 108, 101,  32, 111, 114,  32, 100,
    105, 114, 101,  99,
    ... 416 more items
  ],
  errors: 'PHP Warning:  include(wordpress/wp-load.php): Failed to open stream: No such file or directory in php-wasm run script on line 2\n' +
    "PHP Warning:  include(): Failed opening 'wordpress/wp-load.php' for inclusion (include_path='.:') in php-wasm run script on line 2\n" +
    'PHP Fatal error:  Uncaught Error: Call to undefined function update_option() in php-wasm run script:5\n' +
    'Stack trace:\n' +
    '#0 {main}\n' +
    '  thrown in php-wasm run script on line 5\n',
  exitCode: 2,
  httpStatusCode: 200
}
Blueprint step completed: setSiteOptions
/Users/macbookpro/.npm/_npx/7c65af5c66ec2a7e/node_modules/@php-wasm/node/index.cjs:17841
      throw reason;
      ^

Error: Failed to run code: <br />
<b>Warning</b>:  include(wordpress/wp-load.php): Failed to open stream: No such file or directory in <b>php-wasm run script</b> on line <b>2</b><br />
<br />
<b>Warning</b>:  include(): Failed opening 'wordpress/wp-load.php' for inclusion (include_path='.:') in <b>php-wasm run script</b> on line <b>2</b><br />
<br />
<b>Fatal error</b>:  Uncaught Error: Call to undefined function update_option() in php-wasm run script:5
Stack trace:
#0 {main}
  thrown in <b>php-wasm run script</b> on line <b>5</b><br />
 PHP Warning:  include(wordpress/wp-load.php): Failed to open stream: No such file or directory in php-wasm run script on line 2
PHP Warning:  include(): Failed opening 'wordpress/wp-load.php' for inclusion (include_path='.:') in php-wasm run script on line 2
PHP Fatal error:  Uncaught Error: Call to undefined function update_option() in php-wasm run script:5
Stack trace:
#0 {main}
  thrown in php-wasm run script on line 5

    at Q (file:///Users/macbookpro/.npm/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:502:27)
    at Module.Ce [as setSiteOptions] (file:///Users/macbookpro/.npm/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:486:10)
    at async o (file:///Users/macbookpro/.npm/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:2044:30)
    at async Object.run (file:///Users/macbookpro/.npm/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:2007:21)
    at async yt (file:///Users/macbookpro/.npm/_npx/7c65af5c66ec2a7e/node_modules/@wp-playground/blueprints/index.js:2079:3)
    at async startWPNow (file:///Users/macbookpro/.npm/_npx/7c65af5c66ec2a7e/node_modules/@wp-now/wp-now/main.js:596:5)
    at async startServer (file:///Users/macbookpro/.npm/_npx/7c65af5c66ec2a7e/node_modules/@wp-now/wp-now/main.js:865:42)
    at async Object.handler (file:///Users/macbookpro/.npm/_npx/7c65af5c66ec2a7e/node_modules/@wp-now/wp-now/main.js:1037:25)

Node.js v20.8.1

Expected:
3. Observe the WordPress site opening correctly and non errors appear in the console.

Start in packages/playground/blueprints/src/lib/steps/site-data.ts around line 37 and reproduce the issue with the provided blueprint.json and wp-now command. Trace how setSiteOptions determines the WordPress path, then verify that the same blueprint works with a non-default documentRoot and no console errors.