feat: Allow support for custom wildcard directory in sd-dynamic-prompts

[azmodii]

This PR introduces the following changes:

• Allow support for custom wildcard directory in sd-dynamic-prompts

[azmodii]

Note: I did not test stable-diffusion-webui-wildcards but it appears to use similar syntax:

        wildcards_dir = shared.cmd_opts.wildcards_dir or os.path.join(repo_dir, "wildcards")

I assume the following change would work, but am unable to test (as I don't personally use that extension).

    try:
        from modules.shared import opts, cmd_opts
    except ImportError:  # likely not in an a1111 context
        opts, cmd_opts = None

    wildcard_dir = getattr(opts, "wildcard_dir", None)
    wui_wildcards_dir = getattr(cmd_opts, "wildcards_dir", None)

   ...

    if wui_wildcards_dir is not None:
        wui_wildcards_dir = Path(wui_wildcards_dir)
        if wui_wildcards_dir.exists():
            found.append(wui_wildcards_dir)

[DominikDoom]

The normal webui argument won't need the getattr syntax since both cmd args and normal options settable through the UI have a default value, making it even simpler. Scratch that, since it's only available with the extension active it's still needed. But nonetheless very simple like you suggested. I'll add it alongside.

For whatever reason sd-dynamic-prompts doesn't expose the path setting in the UI, so that's why they need to use the function themselves (for providing a default value instead of throwing an error).