Internal integrations - Add input for scoping webhooks per project

### Problem Statement My webhook is noisy and firing too often. I am interested in scoping it to only accept events for some projects, but have to manually do that through the terminal. ### Solution Brainstorm We already have the logic to scope the webhook for a specific project, or multiple projects by calling that endpoint (full steps outlined in [#85502](<https://github.com/getsentry/sentry/issues/85502>)). Can we add an input field or something else, inside of the internal integrations "webhooks" section to allow configuring it for select projects?  Could look like our inbound filters input, but instead nested under "webhooks" for projects.  Then send the body: ``` { projects: ['project-1', 'project-2'] } ``` [https://github.com/getsentry/sentry/pull/85502#issue-2864731015](<https://github.com/getsentry/sentry/pull/85502#issue-2864731015>) ### Product Area Settings - Integrations We want to define a set of [lightweight metrics](<https://docs.sentry.io/product/explore/metrics/>) that SDKs can automatically collect for e.g. framework, language or platform, focusing only on signals that…