ref(integrations): Make ReportTypes a const enum

[AbhiPrasad]

ReportTypes is an interally used enum, so we do not need the runtime support. The ReportTypes enum lives in packages/integrations/src/reportingobserver.ts and is used by the ReportingObserver integration to manage report types.

According to the TS docs: https://www.typescriptlang.org/docs/handbook/enums.html

Const enums can only use constant enum expressions and unlike regular enums they are completely removed during compilation. Const enum members are inlined at use sites. This is possible since const enums cannot have computed members.

This helps save on bundle size.

[github-actions]

size-limit report

Path	Base Size (846e732)	Current Size	Change
@sentry/browser - CDN Bundle (gzipped)	22.48 KB	22.49 KB	+0.01% 🔺
@sentry/browser - Webpack	23.37 KB	23.37 KB	0%
@sentry/react - Webpack	23.4 KB	23.4 KB	0%
@sentry/nextjs Client - Webpack	49.73 KB	49.73 KB	0%
@sentry/browser + @sentry/tracing - CDN Bundle (gzipped)	29.93 KB	29.93 KB	+0.01% 🔺

[lobsterkatie]

Same suggestion here as on #4210:

...so we do not need the runtime support. This helps save on bundle size.

Suggestion: ...so we don't need its underlying values to be meaningful at runtime. Making it a const enum allows TS to convert those values to inlined integers, thereby decreasing bundle size.

You also might consider mentioning, in the title and/or the description, that ReportTypes is part of ReportingObserver, just so people don't have to click through to the Files tab to figure that out.

[AbhiPrasad]

Updated description