[Matter.framework] Follow-up to address remaining issues from #36015 (#36064)

* [Matter.framework] Follow-up to address remaining issues from #36015

* Update src/darwin/Framework/CHIP/MTRBaseDevice.mm

Co-authored-by: Boris Zbarsky <bzbarsky@apple.com>

---------

Co-authored-by: Boris Zbarsky <bzbarsky@apple.com>

Author: vivien-apple

src/darwin/Framework/CHIP/MTRBaseDevice.mm

@@ -1894,7 +1894,7 @@ NSTimeInterval MTRTimeIntervalForEventTimestampValue(uint64_t timeValue)
     uint64_t eventTimestampValueSeconds = timeValue / chip::kMillisecondsPerSecond;
     uint64_t eventTimestampValueRemainderMilliseconds = timeValue % chip::kMillisecondsPerSecond;
     NSTimeInterval eventTimestampValueRemainder
-        = NSTimeInterval(eventTimestampValueRemainderMilliseconds / static_cast<uint64_t>(chip::kMillisecondsPerSecond));
+        = NSTimeInterval(eventTimestampValueRemainderMilliseconds) / static_cast<double>(chip::kMillisecondsPerSecond);
     NSTimeInterval eventTimestampValue = eventTimestampValueSeconds + eventTimestampValueRemainder;
 
     return eventTimestampValue;

src/darwin/Framework/CHIP/MTRConversion.h

@@ -38,7 +38,7 @@ AsNumber(chip::Optional<T> optional)
 
 inline NSDate * MatterEpochSecondsAsDate(uint32_t matterEpochSeconds)
 {
-    const uint64_t interval = static_cast<uint32_t>(chip::kChipEpochSecondsSinceUnixEpoch) + matterEpochSeconds;
+    const auto interval = static_cast<uint64_t>(chip::kChipEpochSecondsSinceUnixEpoch) + static_cast<uint64_t>(matterEpochSeconds);
     return [NSDate dateWithTimeIntervalSince1970:(NSTimeInterval) interval];
 }