Expose sessionPersistence parameter to Flutter SDK

[mikklfr]

Feature description

Hello,

Would be appreciated to allow Flutter Web devs to provide the sessionPersistence parameter for RUM and Logs.
[Documentation](https://datadoghq.dev/browser-sdk/interfaces/_datadog_browser-rum.RumInitConfiguration.html#sessionpersistence)

Without this, the easiest workaround on Flutter Web is to patch the .js SDK files to override switch cases and force local-storage instead of cookies.
This breaks the use of CDN and will prevent the use of the latests versions automatically.

Proposed solution

Add sessionPersistence parameters to RUM and Logs features

Other relevant information

No response

[fuzzybinary]

Hi @mikklfr ,

Thanks for reporting. This is on our radar to fix but likely won't make it until our first release of v3. I'll keep this ticket posted on progress.

[mikklfr]

Thanks, will keep on eye on it!