feat: add NMS integration with TLS

[patriciareinoso]

Description

This PR adds the NMS integration with the TLS to the integration tests.
TLS certificates integration is mandatory for NMS and the NMS charm does not share the webui address until this relation exists.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that validate the behaviour of the software
• I validated that new and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have bumped the version of the library