Web page details schema: `homePage` and `errorPage` property keys mis-matched between JSON and Examples

## What are the schemas that are affected by the issue

https://ns.adobe.com/xdm/context/webpagedetails

[docs/reference/context/webpagedetails.schema.json](https://github.com/adobe/xdm/blob/master/docs/reference/context/webpagedetails.schema.json)

## What are examples of products that are impacted by the issue
Adobe Analytics

### Details

When viewing the webpagedetails schema, it specifies the keys `xdm:isErrorPage` and `xdm:isErrorPage`. Looking at the example and corresponding markdown doc, the keys `xdm:errorPage` and `xdm:homePage` are used.

Which definition is correct (i.e. expected by AEP backend)?

Start by comparing docs/reference/context/webpagedetails.schema.json with the linked example and corresponding markdown documentation, focusing on the homePage and errorPage keys. Determine which names the AEP backend expects, then make the schema, example, and markdown use the same definitions and verify the discrepancy is resolved.

Written by the indexing model from the issue text.