Fix timing metric value different from span duration

[stefanosiano]

📜 Description

removed timing from IMetricsAggregator
duration of timing metric of MetricsApi now equals span duration
local metrics aggregator is fetch directly from the span in the timing api

💡 Motivation and Context

Fixes #3289 and #3290

💚 How did you test it?

Unit tests

📝 Checklist

• I reviewed the submitted code.
• 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.
• 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

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	402.45 ms	470.40 ms	67.95 ms
Size	1.70 MiB	2.28 MiB	592.12 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
0810952	364.51 ms	468.08 ms	103.57 ms
baaf637	462.32 ms	579.22 ms	116.90 ms
1e05e43	411.00 ms	467.29 ms	56.29 ms
86f0096	371.86 ms	439.78 ms	67.92 ms
baaf637	401.69 ms	428.12 ms	26.43 ms
937879e	400.98 ms	482.84 ms	81.86 ms
1ae2ec6	353.85 ms	419.71 ms	65.85 ms
606074f	385.10 ms	428.24 ms	43.14 ms
9119d59	407.12 ms	509.64 ms	102.52 ms
93a76ca	391.54 ms	475.65 ms	84.11 ms

App size

Revision	Plain	With Sentry	Diff
0810952	1.72 MiB	2.27 MiB	558.21 KiB
baaf637	1.72 MiB	2.27 MiB	558.42 KiB
1e05e43	1.70 MiB	2.28 MiB	590.89 KiB
86f0096	1.72 MiB	2.29 MiB	576.50 KiB
baaf637	1.72 MiB	2.27 MiB	558.42 KiB
937879e	1.72 MiB	2.27 MiB	558.42 KiB
1ae2ec6	1.70 MiB	2.27 MiB	584.63 KiB
606074f	1.70 MiB	2.27 MiB	582.26 KiB
9119d59	1.70 MiB	2.27 MiB	583.84 KiB
93a76ca	1.72 MiB	2.29 MiB	576.75 KiB

[markushi]

Nice!