Improve low storage error formatting (EXPOSUREAPP-2745) (#1292)

* Try to use formatted error messages if available.

* Try to use formatted error messages if available.

* If there is no fallback appconfig yet, abort early to show a more accurate error (download error vs "no app config" error).

* Revert "If there is no fallback appconfig yet, abort early to show a more accurate error (download error vs "no app config" error)."

This reverts commit 10ff8f4f

Co-authored-by: harambasicluka <64483219+harambasicluka@users.noreply.github.com>