book 7 session 1-2: drop a hallucinated duplicate line ('Side. Sides.' twice)

The word-list activity had 'Side. Sides.' on two consecutive lines: the second
reused the SAME audio range as the first but carried the NEXT item's picture, so
the learner saw a triangle and heard 'Side. Sides.' (Elena). The tape says it
once, with silence until 'Triangle.' — the line was invented in conversion.
Scanned all 12 books for the signature (same text + same clip range + different
image): the other 9 hits are legitimate drills asking one repeated question
about different pictures.

Co-authored-by: Cursor <cursoragent@cursor.com>

book-7-lesson-1.module

@@ -226,7 +226,6 @@ VOCAB: side
 VOCAB: sides
 LINE: Side. Sides. {page_013_006.jpg} {bk07-l1a-f3-06.mp3}
 
-LINE: Side. Sides. {page_013_007.jpg} {bk07-l1a-f3-07.mp3}
 
 VOCAB: triangle
 VOCAB: triangles