meta: Don't gitignore .d.ts files

[lforst]

Was looking at getsentry/sentry-capacitor#249 and getsentry/sentry-capacitor#394 and trying to fix this by adding a bunch of .d.ts files but they were gitignored.

I don't think we should blanket-ignore dts files so this pr removes it from gitignore.

[github-actions]

size-limit report 📦

Path	Size
@sentry/browser - ES5 CDN Bundle (gzipped + minified)	21.95 KB (0%)
@sentry/browser - ES5 CDN Bundle (minified)	69.13 KB (0%)
@sentry/browser - ES6 CDN Bundle (gzipped + minified)	20.28 KB (0%)
@sentry/browser - ES6 CDN Bundle (minified)	60.38 KB (0%)
@sentry/browser - Webpack (gzipped + minified)	21.9 KB (0%)
@sentry/browser - Webpack (minified)	71.51 KB (0%)
@sentry/react - Webpack (gzipped + minified)	21.92 KB (0%)
@sentry/nextjs Client - Webpack (gzipped + minified)	50.57 KB (0%)
@sentry/browser + @sentry/tracing - ES5 CDN Bundle (gzipped + minified)	30.11 KB (+0.01% 🔺)
@sentry/browser + @sentry/tracing - ES6 CDN Bundle (gzipped + minified)	28.14 KB (0%)
@sentry/replay ES6 CDN Bundle (gzipped + minified)	49.42 KB (+0.01% 🔺)
@sentry/replay - Webpack (gzipped + minified)	43.1 KB (0%)
@sentry/browser + @sentry/tracing + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	69.5 KB (+0.01% 🔺)
@sentry/browser + @sentry/replay - ES6 CDN Bundle (gzipped + minified)	61.82 KB (0%)

[mydea]

yeah, I noticed this as well some time in the past, makes sense to me!

[Lms24]

Considering we're gitignoring ./build anyway, I think this is fine!