Move `avg_request_time_to_error` to the backend `context`

[akolson]

Overview

The avg_request_time_to_error property is more suited for the backend context and should be move there instead. Its currently part of errorreport.

Description and outcomes

• Move avg_request_time_to_error to the backend context

Acceptance Criteria

• avg_request_time_to_error is part of the backend context

Assumptions and Dependencies

• NA

Scope

• Moving the avg_request_time_to_error

Accessibility Requirements

NA

Resources

[thesujai]

I can pick this up @akolson

[rtibbles]

Fixed in #12660