[Feature]: support sessionStorage option for storageState persistence & restoration

### 🚀 Feature Request

[`storageState` | TestOptions | Playwright](https://playwright.dev/docs/api/class-testoptions#test-options-storage-state) is very convenient. I appreciate that [Session storage | Authentication | Playwright](https://playwright.dev/docs/auth#session-storage) outlines how to also persist and restore `sessionStorage` but it would be even more convenient to have a built-in option.

### Example

```ts
await page.context().storageState({ path: authFile, includeSessionStorage: true });
```

or, if richer control is desired:

```ts
await page.context().storageState({
path: authFile,
origins: {
"http://localhost:3000": ["localStorage", "sessionStorage"],
"https://example.com": ["sessionStorage"],
"https://www.iana.org": [],
"*": ["localStorage"]
},
});
```

### Motivation

Needing to write the extra code for interacting with the filesystem, stringifying and parsing JSON, adding the init script, etc. isn't too terrible but storing an access token in `sessionStorage` seems common enough to support out-of-the-box.

Start with the storageState TestOptions API and the session-storage Authentication documentation linked in the issue. Trace the storageState entry point and determine how sessionStorage persistence and restoration should fit the proposed option shapes. Done means a settled API design, implementation, documentation, and coverage for saving and restoring sessionStorage.

Written by the indexing model from the issue text.