Problems with text containing NUL character

#### System information:
- Operating system (distribution) and version: Ubuntu 20.10
- DBeaver version: Version 21.0.1.202103220618
- Additional extensions: none

#### Connection specification:
- Database name and version: mariadb 10.2
- Driver name: mariadb 1.5.5
- Do you use tunnels or proxies (SSH, SOCKS, etc)? no

#### Describe the problem you're observing:
Content after a NUL character is truncated without a warning.

Sidenote: The steps below are for the editor only, but it also occurs in the grid view of tables with cells containing NUL characters (most likely also the cause of #5751). When switching to Text view the content is displayed.

#### Steps to reproduce, if exist:
1. Extract the test.sql file from the [test.zip attached here](https://github.com/dbeaver/dbeaver/files/6236706/test.zip) or create a file containing a NUL character
2. Open the test.sql file in the editor.
3. The content after the NUL Character is silently dropped. There should be a warning at least.

#### Include any warning/errors/backtraces from the logs

No errors in error log