CRITICAL FIX: Handle grep failures with set -eo pipefail in scanner installation

FIXED:
- Added '|| true' to all grep commands that filter installation output
- ClamAV installation: Fixed grep exit code issue on yum/apt-get output
- Maldet installation: Fixed signature update grep failure handling
- ImunifyAV installation: Fixed deployment script grep and update grep failures
- Changed imunify update from pipe-to-grep-or-retry to proper if-statement check

BEHAVIOR CHANGE:
- Installation continues even if output patterns don't match expected strings
- Signature updates now use if-statement with grep -q instead of bare pipes
- Better status reporting: shows 'unclear' instead of error when status unknown

ROOT CAUSE:
With 'set -eo pipefail' enabled, grep commands that return 1 (no match) cause
the entire pipeline to fail. This was causing the installation to exit with code 1
even though the software was actually installing successfully.

EXAMPLE:
Before: yum output 'Complete!' → grep looks for 'Installing' → grep returns 1 → exit
After: yum output 'Complete!' → grep returns 1 → handled with '|| true' → continue

modules/security/malware-scanner.sh

@@ -223,13 +223,13 @@ install_all_scanners() {
             if rpm -qa | grep -q "cpanel-clamav"; then
                 echo -e "${GREEN}✓ ClamAV already installed (cPanel)${NC}"
             else
-                /scripts/update_local_rpm_versions --edit target_settings.clamav installed 2>/dev/null
-                /scripts/check_cpanel_rpms --fix --targets=clamav 2>&1 | grep -E "Installing|Updating|up to date"
+                /scripts/update_local_rpm_versions --edit target_settings.clamav installed 2>/dev/null || true
+                /scripts/check_cpanel_rpms --fix --targets=clamav 2>&1 | grep -E "Installing|Updating|up to date" || true
             fi
         elif command -v yum &>/dev/null; then
-            yum install -y clamav clamav-update 2>&1 | grep -E "Installing|Updating|already installed"
+            yum install -y clamav clamav-update 2>&1 | grep -E "Installing|Updating|already installed" || true
         elif command -v apt-get &>/dev/null; then
-            apt-get update && apt-get install -y clamav clamav-daemon
+            apt-get update && apt-get install -y clamav clamav-daemon || true
         fi
 
         if is_clamav_installed; then
@@ -374,7 +374,7 @@ install_all_scanners() {
 
         if [ -f imav-deploy.sh ]; then
             # Run deployment script with progress indicators
-            bash imav-deploy.sh 2>&1 | grep -E "Installing|Installed|Complete|Error|Failed" || bash imav-deploy.sh
+            bash imav-deploy.sh 2>&1 | grep -E "Installing|Installed|Complete|Error|Failed" || true
             rm -f imav-deploy.sh
 
             # Enable cPanel UI plugin if installed