test: remove obsolete environment variable tests

tests/clean_system_maintenance.bats

@@ -455,42 +455,6 @@ EOF
     [[ "$output" != *"SHOULD_NOT_CALL_SOFTWAREUPDATE"* ]]
 }
 
-@test "check_macos_update respects MO_SOFTWAREUPDATE_TIMEOUT" {
-    run bash --noprofile --norc <<'EOF'
-set -euo pipefail
-source "$PROJECT_ROOT/lib/core/common.sh"
-source "$PROJECT_ROOT/lib/check/all.sh"
-
-defaults() { echo "1"; }
-
-export MO_SOFTWAREUPDATE_TIMEOUT=15
-
-run_with_timeout() {
-    local timeout="${1:-}"
-    shift
-    if [[ "$timeout" != "15" ]]; then
-        echo "BAD_TIMEOUT:$timeout"
-        return 124
-    fi
-    if [[ "${1:-}" == "softwareupdate" && "${2:-}" == "-l" && "${3:-}" == "--no-scan" ]]; then
-        echo "No new software available."
-        return 0
-    fi
-    return 124
-}
-
-start_inline_spinner(){ :; }
-stop_inline_spinner(){ :; }
-
-check_macos_update
-echo "TEST_PASSED"
-EOF
-
-    [ "$status" -eq 0 ]
-    [[ "$output" == *"TEST_PASSED"* ]]
-    [[ "$output" != *"BAD_TIMEOUT:"* ]]
-}
-
 @test "check_macos_update outputs debug info when MO_DEBUG set" {
     run bash --noprofile --norc <<'EOF'
 set -euo pipefail