fix(otel): Make sure we handle when sentry-trace is an empty array

[AbhiPrasad]

When testing with a GRPC example I found that the carrier can return an empty array for some values. This checks for that, and adds a validation test.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	19.84 KB (-0.01% 🔽)
@sentry/browser - ES5 CDN Bundle (minified)	61.46 KB (0%)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	18.61 KB (+0.02% 🔺)
@sentry/browser - ES6 CDN Bundle (minified)	55 KB (0%)
@sentry/browser - Webpack (gzipped + minified)	20.37 KB (0%)
@sentry/browser - Webpack (minified)	66.54 KB (0%)
@sentry/react - Webpack (gzipped + minified)	20.4 KB (0%)
@sentry/nextjs Client - Webpack (gzipped + minified)	47.63 KB (0%)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	26.82 KB (+0.02% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	25.25 KB (-0.01% 🔽)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	43.35 KB (-0.83% 🔽)
@sentry/replay - Webpack (gzipped + minified)	38.58 KB (-0.97% 🔽)