This PR makes the following changes:

• An empty "cdi-spec-dirs" in the daemon config or specifying --cdi-spec-dir="" will disable CDI injection even if experimental mode is enabled.
• The configured value for cdi-spec-dirs is added to the system info output. Note that an empty slice is explicitly output. This is a follow-up to the changes adding CDI support as per Add support for CDI devices under Linux #45134 (comment).

- What I did

Added the configured cdi-spec-dirs to the system info output.

- How I did it

• Moved the initialisation to the default options to loadDaemonCliConfig to handle the case where the option is not set to an empty slice.
• Updated the system.Info struct with a CDISpecDirs field that is filled from the config option when daemon.SystemInfo is called.

- How to verify it

The change includes unit tests to ensure that the applied setting is returned.

- Description for the changelog

• Disable CDI device injection if cdi-spec-dirs is empty or set to a single empty string using the command line arguments.
• Added CDISpecDirs to system info output.

- A picture of a cute animal (not mandatory but encouraged)