Description of problem:
In a closed VM detail page, when setting the memory, change "Maximum allocation" to not "128MB" firstly. Then, re-open the setting dialog, and set "Maximum allocation" to "128MB", the dialog could not be closed after clicking "Save"

Version-Release number of selected components (if applicable):
cockpit-machines-292-1.el8.noarch
cockpit-292-1.el8.x86_64
libvirt-dbus-1.3.0-2.module+el8.8.0+16781+9f4724c2.x86_64

How reproducible:
100%

Steps to Reproduce:
1 Create a closed VM, then enter the VM detail page
2 Change "Maximum allocation" to not "128MB" firstly
3 Re-open the setting dialog, and set "Maximum allocation" to "128MB",

Actual results:
1 After step 3, the dialog could not be closed

Expected results:
1 After step 3, the dialog could be closed

Additional info: