You have the wrong type in ContentSearchIndexConfiguration. Change from
<ContentSearchIndexConfiguration type="Sitecore.ContentSearch.Azure.CloudSearchProviderIndex, Sitecore.ContentSearch.Azure">
<ContentSearchIndexConfiguration type="Sitecore.ContentSearch.Azure.CloudIndexConfiguration, Sitecore.ContentSearch.Azure">
The best way to ...
After investigating I found that this error occured in Avatar facet.
It looks like sitecore indexer bug.
This issue happens when image for avatar has a big/medium resolution. Image data (byte) is big and as I understand there are some limits in JsonReader or somewhere else.
After many attempts I found that 128x128 jpeg image is OK and error dissappears, ...
You could call the Azure Search Rest API directly to query the index-catalog
GET xxx.search.windows.net/indexes/index-catalog/docs?search=*&$filter=sitecorename eq 'sitecore_web_index'