lib389 get_db_lib function may returns the wrong db type

[progier389]

Issue Description
lib389 get_db_lib function may returns the default database type instead of the configured one.

Package Version and Platform:

• Platform: CentOS 9
• Package and version: 389-ds-base-2.5.2-1.el9
• Browser: N/A

Steps to Reproduce
Steps to reproduce the behavior:

1. Setup an lmdb instance
2. Run dsctl instance healthcheck
3. See DSBLE0006 and DSBLE0005 errors

Expected results
Healthcheck should not display any errors.

Additional context
Problem is that from backend import DatabaseConfig generate an ImportError so the call to DatabaseConfig(self).get_db_lib() is bypassed.
It should rather be:from lib389.backend import DatabaseConfig

[progier389]

Triaged: https://issues.redhat.com/browse/IDMDS-4635

[vashirov]

effca98..f21ba5e 389-ds-base-2.5 -> 389-ds-base-2.5
62d9677..3497a86 389-ds-base-2.6 -> 389-ds-base-2.6
d6ad2ae..c0cbfc4 389-ds-base-3.0 -> 389-ds-base-3.0