Install python3-dns and pytest

BIND 9.16 still provides python3 modules and can test them using pytest.
cds test can use python3-dns, if it is installed.

Sanity/Run-internal-BIND-test-suite/main.fmf

@@ -31,6 +31,7 @@ recommend:
   - dnf-utils
   - rng-tools
   - gcc-c++
+  - python3-dns
 adjust:
   - enabled: false
     when: distro == rhel
@@ -47,6 +48,7 @@ adjust:
   - recommend+:
       - bind9.16
       - bind9.16-utils
+      - pytest
     environment+:
       PACKAGE: bind9.16
     when: component == bind9.16