polish connection impersonation FE (#31708)

e2e/test/scenarios/permissions/impersonated.cy.spec.js

...ions/components/ImpersonationModal/ImpersonationModal.tsx

...nents/ImpersonationModal/ImpersonationModal.unit.spec.tsx

.../components/ImpersonationModal/ImpersonationModalView.tsx

frontend/src/metabase-types/api/mocks/permissions.ts

...omponents/PermissionsPageLayout/PermissionsPageLayout.tsx

...tabase/admin/permissions/hooks/use-leave-confirmation.jsx

...se/admin/permissions/selectors/data-permissions/fields.ts

...e/admin/permissions/selectors/data-permissions/schemas.ts

...se/admin/permissions/selectors/data-permissions/shared.ts

...se/admin/permissions/selectors/data-permissions/tables.ts

frontend/src/metabase/components/Modal/WindowModal.tsx

...metabase/core/components/FormFooter/FormFooter.styled.tsx

frontend/test/__support__/server-mocks/impersonation.ts

frontend/test/__support__/server-mocks/user.ts