Description of problem:
Create Subnets wizard accepts CIDR in the Network Address field, resulting in an invalid CIDR being generated on the Subnets page.

Version-Release number of selected component (if applicable):
6.13.1

How reproducible:
Always (100%)

Steps to Reproduce:
1. In the hamburger menu in the top left, open tab Infrastructure and click on Subnets
2. In top right of the resulting view, click Create Subnet button
3. Enter any name into the Name field
4. Pick IPv4 as the protocol
5. Under network address, enter CIDR (ex. 10.0.1.0/25) instead of network address (10.0.1.0 in my example)
6. Under Network prefix, enter the network's prefix - 25
7. Click Submit

Actual results:
Once submitted, you're redirected back to the Subnets list, where the network's address shows up as 10.0.1.0/25/25, like in the attachment.

Expected results:
Option 1 (ideal): when user's cursor leaves the field, attempt finding the network prefix (the part after '/' in CIDR) and insert it into its field (Network Prefix)
Option 2: when user's cursor leaves the field, report an invalid address
Option 3: once submitted, report an invalid address

Additional info:
Accepted by editing an existing network as well.
This could potentially break more things, haven't looked further.