feat: add client upload time

[Mercy811]

Summary

https://amplitude.atlassian.net/browse/AMP-87210 Adding client_upload_time so that when client-side clock is drifted, backend can correct it

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[github-actions[bot]]

:tada: This PR is included in version 1.12.0 :tada:

The release is available on:

• GitHub release
• v1.12.0

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