test: Adjust TestLogin.testSELinuxRestrictedUser on rhel-8-3-distropkg
test: Adjust TestLogin.testSELinuxRestrictedUser on rhel-8-3-distropkg

RHEL 8.3 has Cockpit 224 now, and thus an SELinux friendly memfd
handling. Remove the special case.

Closes #14426
martinpitt/cockpit,moraleslazaro/cockpit,garrett/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,deryni/cockpit,deryni/cockpit,deryni/cockpit,deryni/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,garrett/cockpit,garrett/cockpit,mvollmer/cockpit,deryni/cockpit,mvollmer/cockpit,garrett/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit,martinpitt/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,deryni/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,mvollmer/cockpit,garrett/cockpit,mvollmer/cockpit,deryni/cockpit