fix: do not try to access private runtime config on client

[danielroe]

Description

resolves #54
nuxt/nuxt#27555

We now log (in dev mode only) when users try to access private runtime config on the client.

This ensures we don't try to do that in this module.

Linked Issues

Additional context

[harlan-zw]

Thank you for the help, much appreciated 🙌

[robmontesinos]

Getting this warning in dev mode as listed above:
Could not access nuxt-schema-org. The only available runtime config keys on the client side are 'public' and 'app'. See https://nuxt.com/docs/guide/going-further/runtime-config` for more information.`

We are not accessing runtime config in relation to NuxtSEO at all in our project; it seems like NuxtSEO is doing the accessing. Furthermore the LD+JSON object is not being created in the head. Can you possibly provide more information as to how to locate and correct this warning?

FYI: When I use the documents to add settings to nuxt config:

siteConfig: { title: 'Nuxt SEO', description: 'Nuxt SEO is a collection of hand-crafted Nuxt Modules to help you rank higher in search engines.', url: 'https://nuxtseo.com' },

I get the following error:
Object literal may only specify known properties, and 'siteConfig' does not exist in type 'InputConfig<NuxtConfig, ConfigLayerMeta>'.

Any help with this important element would be appreciated.