Allow to call `misc.sysprof.report()` when sysprof is running

Current version of sysprof doesn't allow to call `misc.sysprof.report()` when sysprof is running:

```lua
Tarantool 3.4.0-entrypoint-198-gc7ff154f7f
type 'help' for interactive help
tarantool> misc.sysprof.start()
---
- true
...

tarantool> misc.sysprof.report()
---
- null
- profiler misuse
- 22
...

tarantool> 
```

However, observing counters could be useful when profiling is not finished.