Improve performance of ConfigOverrides in Social Lazy Load

Problem/Motivation

The SocialLazyLoadingImageDisplayOverride and SocialLazyLoadingTextFormatOverride are checking for existing config. This is adding an extra few 100ms to a page request as this code is executed via lazy_is_enabled() in lazy.module

Proposed resolution

Let's remove the configfactory injects inside these overrides and simplify the code a bit.