feat(insights): add view trends button in frontend domain view

[DominikB2014]

Work for (https://github.com/getsentry/sentry/issues/77572)

Adds a "view trends" button at the top right of the frontend domain overview page

This will be repeated for all domain views. (Also yes, we are looking into sharing a lot of these header stuff eventually).

I had to move the <layout.header> up into the FrontendHeader component, otherwise the button wouldn't be properly positioned (because <Layout.HeaderActions> wouldn't be a direct child of <Layout.Header>