Feature Request: Email based member access to usage and spend tabs in billing

Feature request Is your feature request related to a problem? When users on a team need to see their organization's PostHog usage and spend, they can't. The billing page (the Usage and Spend tabs at /organization/billing) is restricted to org Admins and Owners, and Members get no access at all. The only way to let someone monitor cost today is to make them an Admin, which also gives them control over members, projects, SSO/auth settings, RBAC, reverse proxies, and org settings. So an admin either over-grants access to people who only need to monitor spend (for example, finance or an engineering lead), or those people stay blind to it and have to ask an admin every time. Describe the solution you'd like Let an Admin or Owner grant a Member read-only access to the Usage and Spend tabs. The Member could see current usage, spend, and history, but couldn't change anything: no changing the plan, no setting or raising billing limits, no adding or removing products, no e…