CI: don't use multiple lines in a for loop

For some reason gitlab doesn't like it.

It worked with the line

for ext in exe msi 7z zip; do mv ${SHORTARCH}/vlc--dev-.{ext} nightlies/(basename ${SHORTARCH}/vlc--dev-.{ext} | sed "s/.{ext}/-{CI_COMMIT_SHORT_SHA}.{ext}/"); done

It should work with the line

for ext in exe msi 7z zip; do mv ${SHORTARCH}/vlc--dev-.{ext} nightlies/(basename ${SHORTARCH}/vlc--dev-.{ext} | sed "s/.{ext}/-{CI_COMMIT_SHORT_SHA}.{ext}/") || echo "vlc-*.${ext} not found!"; done

Fixes #27459 (closed) ?