ref: Add argument-less overload to resolvedSyncPromise

[lforst]

Add an overload to resolvedSyncPromise so we can call it without arguments and without having to do resolvedSyncPromise<void>(undefined).

This is inspired by typescripts way of defining Promise.resolve():
https://github.com/microsoft/TypeScript/blob/2a78b225d00170044becdbfe499909e7d6cad68b/lib/lib.es2015.promise.d.ts#L136-L147

Ref: https://getsentry.atlassian.net/browse/WEB-775

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	18.35 KB (-8.87% 🔽)
@sentry/browser - ES5 CDN Bundle (minified)	57.52 KB (-10.98% 🔽)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	17.13 KB (-9.18% 🔽)
@sentry/browser - ES6 CDN Bundle (minified)	51.75 KB (-10.73% 🔽)
@sentry/browser - Webpack (gzipped + minified)	20.94 KB (-9.88% 🔽)
@sentry/browser - Webpack (minified)	72.5 KB (-11.28% 🔽)
@sentry/react - Webpack (gzipped + minified)	20.98 KB (-9.89% 🔽)
@sentry/nextjs Client - Webpack (gzipped + minified)	45.97 KB (-4.34% 🔽)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	24.13 KB (-7.45% 🔽)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	22.64 KB (-7.52% 🔽)