Is dyslexia less common among visually impaired? I couldn't find any information on whether dyslexia is equally prevalent in normally sighted people and among visually impaired people who learned reading and writing through braille?
The term Dyslexia is used to refer to a pattern of learning difficulties
characterized by problems with accurate or fluent word recognition, poor decoding, and poor spelling abilities.

DSM-5 posit: "The learning difficulties are not better accounted for by intellectual disabilities, uncorrected visual or auditory acuity, other mental or neurological disorders, psychosocial adversity, lack of proficiency in the language of academic instruction, or inadequate educational instruction"

This is one of the diagnostic criteria for a "Specific learning disorder".
Accordingly, the answer to your question is no, because in that case we should talk about another deficit.