Simulated throttling edge-case: doesn't account for timeout

### FAQ

- [-] Yes, my issue is not about [variability](https://github.com/GoogleChrome/lighthouse/blob/main/docs/variability.md) or [throttling](https://github.com/GoogleChrome/lighthouse/blob/main/docs/throttling.md).
Note: Didn't find a place to report simulation edge-case scenarios in doc above.
- [x] Yes, my issue is not about a specific accessibility audit (file with [axe-core](https://github.com/dequelabs/axe-core) instead).
- [x] Yes, my issue is not answered by [other FAQs](https://github.com/GoogleChrome/lighthouse#faq).

### URL

https://1um.github.io/lcp-test/lcp-1?fetchCount=40

### What happened?

**Setup:**
Page is shown after timeout or all requests are finished (whatever first).
As fetchCount goes up, LCP is going up, in simulated mode.

**Real world scenario:**
A/B testing script hides page and apply changes before user sees the original (prevent flicking).
If timeout reached, regardless of a/b test, hydration, etc queries, show page as is.

### What did you expect?

LCP is not going up and capped, due to timeout branch.

### What have you tried?

Created minimalistic demo of the issue, to rule out any other variables.

| Scenario | URL | Simulated LCP | DevTools LCP |
|----------------|----------------------------------------------------------------------|----------------|----------------|
| No script | https://1um.github.io/lcp-test/lcp-1?exitEarly=true | 0.9 s | 0.8 s |
| fetchCount=1 | https://1um.github.io/lcp-test/lcp-1?fetchCount=1 | 1.7 s | 1.4 s |
| fetchCount=40 | https://1um.github.io/lcp-test/lcp-1?fetchCount=40 | 3.2 s | 1.7 s |
| fetchCount=100 | https://1um.github.io/lcp-test/lcp-1?fetchCount=100 | 6.3 s | 1.8 s |
| fetchCount=200 | https://1um.github.io/lcp-test/lcp-1?fetchCount=200 | 11.4 s | 1.8 s |

Simulated:

DevTools:

Code:
https://github.com/1um/lcp-test/blob/main/lcp-1.html

### How were you running Lighthouse?

Chrome DevTools

### Lighthouse Version

12.6.0

### Chrome Version

138.0.0.0

### Node Version

_No response_

### OS

MacOS

### Relevant log output

```sh

```