ref(core): Move getSdkMetadataForEnvelopeHeader to utils

[Lms24]

We want to use getSdkMetadataForEnvelopeHeader in Replay to not have duplicated minimal SDKInfo extraction logic. I checked that envelope helper functions are usually publicly exposed from the utils package only (which makes sense to me). So, this PR moves the function from core to utils and calls it in the replay envelope creation function.

Note that I changed the input type to accept both, an Event as well as SdkMetadata, as both have the sdk: SdkInfo property.

Since getSdkMetadataForEnvelopeHeader wasn't exported before, I think we don't have to worry about a breaking change here.

ref: #6366

[mydea]

nice one!

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	19.72 KB (0%)
@sentry/browser - ES5 CDN Bundle (minified)	61.13 KB (0%)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	18.51 KB (-0.01% 🔽)
@sentry/browser - ES6 CDN Bundle (minified)	54.66 KB (0%)
@sentry/browser - Webpack (gzipped + minified)	20.28 KB (0%)
@sentry/browser - Webpack (minified)	66.33 KB (0%)
@sentry/react - Webpack (gzipped + minified)	20.3 KB (0%)
@sentry/nextjs Client - Webpack (gzipped + minified)	47.51 KB (+0.03% 🔺)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	26.69 KB (+0.03% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	25.13 KB (-0.02% 🔽)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	41.87 KB (+0.1% 🔺)
@sentry/replay - Webpack (gzipped + minified)	38.1 KB (+0.05% 🔺)