[Bug] Complete setup pool configuration button stays loading for about 17 seconds

### Describe the bug

When adding or authenticating miners, the `Configure pools` modal in `Complete setup` takes around 17 seconds before the `Configure` button becomes usable.

If the user reloads the page or navigates to another page and comes back, the same flow loads instantly. That suggests the long wait during the initial flow is not intended.

### Preconditions

- Have at least one miner with no mining pool configured

### Steps to reproduce

1. Navigate to `Miners`
2. Delete and re-add a miner, or authenticate a miner
3. Open the `Complete setup` flow
4. Observe the `Configure pools` action

### Expected behavior

The user should be able to click `Configure` for mining pools within a reasonable time.

### Actual behavior

The `Configure` button is disabled and shows a spinner for around 17 seconds before it becomes available.

### Workaround

Refreshing the page or navigating to `Home`, where the same setup flow is also available, makes it load instantly.

### Proto Fleet version

`nightly-20260703-a7b00e867a12-13-g04a0c8c5-dirty`

### Environment

- OS: macOS
- Browser: Chrome

### Screenshots & screen recordings

https://github.com/user-attachments/assets/d4d83eef-c4bd-4519-944f-09b299200b46

Start by reproducing the delay in the Complete setup flow after adding or authenticating a miner, then compare it with the instantly loading flow after a refresh or navigation. Trace the Configure pools action and its loading state. Done means the Configure button becomes usable promptly on the initial flow without requiring a reload.

Written by the indexing model from the issue text.