Fix blob binary state detection for preloaded files

What does this MR do and why?

Contributes to #351559 (closed)

Problem

Blob does not refresh binary status without an explicit blob.load_all_data! call.

Solution

Recalculate binary status if the data was already preloaded.

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Enable feature flags refactor_blob_viewer and highlight_js
2. Visit http://127.0.0.1:3000/gitlab-org/gitlab-test/-/blob/binary-encoding/encoding/binary-1.bin

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.