Add Flutter profiling to onboarding

[vaind]

Problem Statement

Based on #54093, add Profiling to Flutter (currently in alpha and only available for iOS and macOS).

See:

• feat: profiling for iOS/macOS sentry-dart#1611
• feat: flutter profiling docs sentry-docs#8363

Solution Brainstorm

No response

Product Area

Profiling

[getsantry]

Assigning to @getsentry/support for routing ⏲️

[bruno-garcia]

We just need the wizard in the docs repo, like this: https://github.com/getsentry/sentry-docs/tree/master/src/wizard/php/profiling-onboarding/laravel

But under: https://github.com/getsentry/sentry-docs/tree/master/src/wizard/flutter
if we support raw Dart, then also: https://github.com/getsentry/sentry-docs/tree/master/src/wizard/dart

I could get to this next week, if u don't have time @vaind

@JonasBa offered to do the in-product changes.

[vaind]

if we support raw Dart

we don't, it's using sentry-cocoa from the flutter package

[getsantry]

Routing to @getsentry/product-owners-profiling for triage ⏲️