Fix permission race condition in fixPermissions function

Fixes #1583 - Ubuntu 24 permission issues causing 404 errors

Changes:
- Move main public_html permission setting to END of fixPermissions function
- Ensures public_html maintains user:nogroup ownership (not user:user)
- Prevents child domain processing from interfering with main directory permissions
- Changed all async popenExecutioner calls to sync executioner calls
- Reordered operations: permissions first, then ownership

This fixes the issue where clicking "Fix Permissions" in file manager
would incorrectly change public_html group from nogroup to the user's group,
causing 404 errors on Ubuntu 24.

filemanager/filemanager.py

@@ -1068,13 +1068,7 @@ class FileManager:
         command = 'chown -R -P %s:%s /home/%s/public_html/.[^.]*' % (externalApp, externalApp, domainName)
         ProcessUtilities.executioner(command)
 
-        # Set public_html directory itself to user:nogroup with 750 permissions
-        command = 'chown %s:%s /home/%s/public_html' % (externalApp, groupName, domainName)
-        ProcessUtilities.executioner(command)
-
-        command = 'chmod 750 /home/%s/public_html' % (domainName)
-        ProcessUtilities.executioner(command)
-
+        # Process child domains first
         for childs in website.childdomains_set.all():
             command = 'ls -la %s' % childs.path
             result = ProcessUtilities.outputExecutioner(command)
@@ -1105,3 +1099,10 @@ class FileManager:
 
             command = 'chown %s:%s %s' % (externalApp, groupName, childs.path)
             ProcessUtilities.executioner(command)
+
+        # Set public_html directory itself to user:nogroup with 750 permissions (done at the end)
+        command = 'chown %s:%s /home/%s/public_html' % (externalApp, groupName, domainName)
+        ProcessUtilities.executioner(command)
+
+        command = 'chmod 750 /home/%s/public_html' % (domainName)
+        ProcessUtilities.executioner(command)