[ds2484] Fix read64() using uint8_t accumulator instead of uint64_t (#14479)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

esphome/components/ds2484/ds2484.cpp

@@ -110,9 +110,9 @@ uint8_t DS2484OneWireBus::read8() {
 }
 
 uint64_t DS2484OneWireBus::read64() {
-  uint8_t response = 0;
+  uint64_t response = 0;
   for (uint8_t i = 0; i < 8; i++) {
-    response |= (this->read8() << (i * 8));
+    response |= (static_cast<uint64_t>(this->read8()) << (i * 8));
   }
   return response;
 }