Re-order sentences in the Helper image registry section of the Runner Advanced Config doc

Darren Eastmanrequested to merge
DarrenEastman-main-patch-9869 into main

What does this MR do?

Reorder sentences in the Helper image registry section of the Runner Advanced Config doc.

Why was this MR needed?

Documentation review and update for KR 8511

What are the relevant issue numbers?

#37933 (closed)

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