Remove extra space in string comp

Fixes [30983](https://github.com/ansible/ansible/issues/30983)

lib/ansible/modules/cloud/vmware/vmware_guest.py

@@ -925,7 +925,7 @@ class PyVmomiHelper(object):
                 return expected * 1024 * 1024 * 1024
             elif unit == 'gb':
                 return expected * 1024 * 1024
-            elif unit == ' mb':
+            elif unit == 'mb':
                 return expected * 1024
             elif unit == 'kb':
                 return expected