Changes to Web Search

removed subschema #2 from the request body oneOf list

added subschema #2 subschema #3 to the request body oneOf list

added subschema #3 subschema #4 to the mode request property anyOf list

added the new optional request property mode

added the new optional request property provider

added subschema #1 subschema #2 to the request body oneOf list

endpoint added