ref(core): Avoid boxing in DateUtils.nanosToDate

[runningcode]

📜 Description

Implementing @0xadam-brown 's suggestion here: https://github.com/getsentry/sentry-java/pull/5520/changes#r3387804225

DateUtils.nanosToDate stored the result of nanosToMillis(...) — which already returns a primitive double — in a boxed Double, then unboxed it again via millis.longValue(). This change keeps the value primitive and replaces the unbox with a plain (long) cast.

// before
final Double millis = nanosToMillis((double) nanos); // box
return getDateTime(millis.longValue());              // unbox

// after
final double millis = nanosToMillis((double) nanos);
return getDateTime((long) millis);

📝 Checklist

• I added GH Issue ID & Linear ID
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

None.

[sentry]

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
SDK Size	io.sentry.tests.size	8.43.1 (1)	release

⚙️ sentry-android Build Distribution Settings

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	321.80 ms	346.08 ms	24.29 ms
Size	0 B	0 B	0 B

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
5b66efd	308.67 ms	363.85 ms	55.18 ms
648fbf7	314.87 ms	358.48 ms	43.61 ms
4c04bb8	350.71 ms	413.63 ms	62.92 ms
ee747ae	396.82 ms	441.67 ms	44.86 ms
ad8da22	365.86 ms	427.00 ms	61.14 ms
d15471f	294.13 ms	399.49 ms	105.36 ms
96eeafa	361.43 ms	455.07 ms	93.63 ms
4fc476b	280.63 ms	363.04 ms	82.42 ms
ee747ae	382.73 ms	435.41 ms	52.68 ms
604a261	380.65 ms	451.27 ms	70.62 ms

App size

Revision	Plain	With Sentry	Diff
5b66efd	1.58 MiB	2.13 MiB	559.07 KiB
648fbf7	0 B	0 B	0 B
4c04bb8	0 B	0 B	0 B
ee747ae	1.58 MiB	2.10 MiB	530.95 KiB
ad8da22	1.58 MiB	2.29 MiB	719.83 KiB
d15471f	1.58 MiB	2.13 MiB	559.54 KiB
96eeafa	1.58 MiB	2.19 MiB	620.21 KiB
4fc476b	0 B	0 B	0 B
ee747ae	1.58 MiB	2.10 MiB	530.95 KiB
604a261	1.58 MiB	2.10 MiB	533.42 KiB

[0xadam-brown]

super nit: Could just add the PR reference here to the line above, as this is a quick fix. Up to you of course.

[runningcode]

Actually I think we just made a release so I'll need to rebase this PR.