Bug: FancyHologram's reload command occationally load nothing.

### In which plugin has the error occurred?

FancyHolograms

### What happened?

FancyHologram's reload command occationally load nothing.

Why this happen:
fancyhologram reload command will call reloadHolograms(). Then reloadHolograms will call unloadHolograms() and loadHolograms(). In unloadHolograms, the task will be sent to Hologram thread but in loadHolograms, it will be executed in Server thread(Current thread). So occationally loadHolograms() will be executed earlier than unloadHolograms(). Finally, no holograms will be loaded.


### In which software has the error occurred?

Paper

### Plugin version

2.6.0.144

### Server version

1.21.4

### Relevant log output

```shell

```