Update dependency posthog-js to ~1.250.0 (#38844)

This PR contains the following updates:

| Package | Type | Update | Change | Pending |
|---|---|---|---|---|
| [posthog-js](https://posthog.com/docs/libraries/js) ([source](https://redirect.github.com/PostHog/posthog-js)) | dependencies | minor | [`~1.249.0` -> `~1.250.0`](https://renovatebot.com/diffs/npm/posthog-js/1.249.5/1.250.1) | `1.257.0` (+17) |

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### Release Notes

<details>
<summary>PostHog/posthog-js (posthog-js)</summary>

### [`v1.250.1`](https://redirect.github.com/PostHog/posthog-js/releases/tag/v1.250.1): 1.250.1

[Compare Source](https://redirect.github.com/PostHog/posthog-js/compare/v1.250.0...v1.250.1)

##### 1.250.1 - 2025-06-10

### [`v1.250.0`](https://redirect.github.com/PostHog/posthog-js/releases/tag/v1.250.0): 1.250.0

[Compare Source](https://redirect.github.com/PostHog/posthog-js/compare/v1.249.5...v1.250.0)

##### 1.250.0 - 2025-06-09

</details>

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### Configuration

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This PR has been generated by [Renovate Bot](https://redirect.github.com/renovatebot/renovate).

GitOrigin-RevId: d36cfff4c12d36527a129edacdb476f7a135fdf7

Author: convex-renovate-runner[bot]