fix: correct byte size calculation for ATT values set from containers

Author: srgg

src/NimBLEAttValue.h

@@ -283,7 +283,10 @@ class NimBLEAttValue {
     typename std::enable_if<Has_data_size<T>::value, bool>::type
 #  endif
     setValue(const T& v) {
-        return setValue(reinterpret_cast<const uint8_t*>(v.data()), v.size());
+        return setValue(
+            reinterpret_cast<const uint8_t*>(v.data()),
+            v.size() * sizeof(typename T::value_type{}) // Calculate effective size in bytes
+        );
     }
 
 # else