Adding dynamic project token from url param projectToken

[santigracia]

• found a way of not using Router and use the window.location searchParams

• needed to use useEffect because of the new tab functionality, switching between tabs changes the DOM and we need to update proj token accordingly

• based on current element structure, I couldn't find an alternative to querySelectorAll().find to select that DOM element.

• Applied the code only to the needed SDKs sections: Javascript, Android, Swift, Obj-C according to onboarding guide here: https://mixpanel.com/report/project_id/view/view_id/setup/