fix: Don't set incompatible platform on Sentry events

[lforst]

#1669 broke symbolication in Sentry because web:javascript is not a platform that Sentry understands.

Sentry uses the platform field to understand how to symbolicate an error and if it is an unknown value it bails. The code can be found here: https://github.com/getsentry/sentry/blob/c1fcd79e4bcd67f25e2b570e424e0758b5ee167f/src/sentry/lang/javascript/processing.py#L178-L180

The previously introduced change mutated the Sentry event in an incompatible way that is compatible with posthog. This change switches over to copying instead of mutating so that we don't break the contract with Sentry.

Note: I am one of the maintainers of the Sentry JS SDK.

[vercel]

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[greptile-apps]

PR Summary

This PR fixes Sentry error symbolication by preventing mutation of the platform field in Sentry events.

• Modified src/extensions/sentry-integration.ts to copy exception data instead of directly mutating the Sentry event
• Preserves Sentry's expected platform values for proper error symbolication
• Maintains PostHog's ability to track exceptions with its own platform format
• Addresses a regression introduced in PR fix: sentry integration fields #1669 that broke Sentry's error processing
• Ensures compatibility between PostHog and Sentry by respecting Sentry's platform value requirements

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[lforst]

Tagging @oliverb123 because you reviewed the PR that broke things.

[marandaneto]

hi @lforst :D

[lforst]

@marandaneto I can feel some special treatment with this PR 😂

[pauldambra]

fly-by to say thank you for taking time to raise the PR 💖 @lforst