crypto: Make MuHash Remove method efficient

Division of MuHash objects are very expensive and multiplication relatively cheap. The whole idea of introducing and tracking numerator and denominators seperately as a representation of the internal state was so that divisions would be rare. So using divison in the Remove method did not make any sense and was just a silly mistake which is corrected here.

src/crypto/muhash.cpp

@@ -341,6 +341,6 @@ MuHash3072& MuHash3072::Insert(Span<const unsigned char> in) noexcept {
 }
 
 MuHash3072& MuHash3072::Remove(Span<const unsigned char> in) noexcept {
-    m_numerator.Divide(ToNum3072(in));
+    m_denominator.Multiply(ToNum3072(in));
     return *this;
 }