Pin to profile broken

**Describe the bug**

Pin to profile used to work fine. Today I checked, and there was no pinned status on my profile. Other clients showed it fine. So, I tried to pin a new one, and got "unable to pin". Using `2024.08.01.818f58b`, with GoToSocial.

**To Reproduce**

Steps to reproduce the behavior:
1. Go to https://dev.phany.social
2. Pin a status. It will show "status pinned", but it will not be shown as such on the UI.
3. Try pinning again (because "Pin to profile" will still be available to pick), get "unable to pin".

**Expected behavior**

I expect pinned statuses are pinned, and the UI shows the icon, and the option to "Unpin".

**Desktop (please complete the following information):**

- OS: [e.g. iOS]: Linux desktop under Chrome, and latest iOS Safari.
- Browser [e.g. chrome, safari]: Latest Chrome under Linux, and Safari under iOS

**Smartphone (please complete the following information):**

- Device: iPhone 14 Pro Max
- OS: 17.6
- Browser: Safari

Start by reproducing the pinning flow at https://dev.phany.social in Chrome or iOS Safari with the stated GoToSocial version. Trace the entry point for “Pin to profile” and compare the successful status response with the profile display and subsequent “Unpin” option. Done means a pinned status is reflected in the UI and can be unpinned without an “unable to pin” error.

Written by the indexing model from the issue text.