Allow Usercentrics CMP in default server-side CSP (script-src-elem, connect-src)

Description: As an admin integrating consent management via Google Tag Manager, I want the default server-side CSP to allow the Usercentrics CMP by including https://.usercentrics.eu and https://.cmp.usercentrics.eu in script-src-elem and connect-src, so that the CMP can load and communicate without CSP violations. This should mirror existing allowlists for Intercom and HubSpot. Problem: The Usercentrics loader script is blocked on hosted domains because the default server-side CSP header overrides Admin portal CSP settings and omits the required Usercentrics domains from script-src-elem (and related connections from connect-src). Custom CSP rules only apply to custom domains, leaving hosted domains unable to load the CMP via GTM. Benefit: Enabling these domains in the default server-side CSP allows privacy-compliant consent management with Usercentrics on hosted domains without requiring a custom domain setup, reduces integration friction, and aligns the default CSP with other supported third-party tools.