Something went wrong - Nomad UI dies while opening multiple clients in tabs

### Nomad version
Nomad v0.11.3 (8918fc804a0c6758b6e3e9960e4eb2e605e38552)

### Operating system and Environment details
Ubuntu 18.04

### Issue
Opening multiple clients from "Clients" list in new tabs always causes error screen at some point:

```
Error
Something went wrong.

[Go to jobs] [Go to clients]
```

### Reproduction steps
Run 50 VMs. Start opening clients in new browser tabs from Clients section.

### Nomad Server logs (if appropriate)
```
Jun 19 21:04:51 hashistack-2 nomad[20464]: 2020-06-19T21:04:51.362Z [ERROR] http: request failed: method=GET path=/v1/client/allocation/d51e5c3d-0ab6-d994-d021-31732b62f0c3/stats error="session open: session shutdown" code=500
Jun 19 21:04:51 hashistack-2 nomad[20464]: http: request failed: method=GET path=/v1/client/allocation/d51e5c3d-0ab6-d994-d021-31732b62f0c3/stats error="session open: session shutdown" code=500
```

Reproduce the failure by opening multiple clients from the Clients section in new browser tabs while 50 VMs are running. Start with the /v1/client/allocation//stats request and the reported “session open: session shutdown” server error. Done means opening client tabs no longer reaches the error screen and the stats requests complete successfully.

Written by the indexing model from the issue text.