Qt: Session management error on linux

I am getting an error when using `:qt5` backend on linux RHEL 8.8

```
using PyCall
pygui(:qt5)
using PyPlot
fig,ax=subplots()
```

gives this error

"Qt: Session management error: Authentication Rejected, reason : None of the authentication protocols specified are supported and host-based authentication failed"

Other backends work ok. However I get a weird error when using `:tk` backend with the `ImageView` package.

Reproduce the reported sequence using PyCall, pygui(:qt5), PyPlot, and subplots() on Linux RHEL 8.8, then compare it with the working backends. Trace the :qt5 entry point and Qt session-management error; done means the reported authentication error is resolved or its supported configuration is documented.

Scritto dal modello di indicizzazione a partire dal testo della issue.