UI: Fix VPC network offerings listing on VPC tier creation

[nvazquez]

Description

This PR fixes the VPC network offerings listing on VPC tiers creation Fixes: #8023

Types of changes

• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] New feature (non-breaking change which adds functionality)
• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] Enhancement (improves an existing feature and functionality)
• [ ] Cleanup (Code refactoring and cleanup, that may add test cases)
• [ ] build/CI
• [ ] test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• [ ] Major
• [x] Minor

Bug Severity

• [ ] BLOCKER
• [ ] Critical
• [ ] Major
• [x] Minor
• [ ] Trivial

Screenshots (if appropriate):

How Has This Been Tested?

Create VPC offering with Lb as supported service and VpcVirtualRouter as provider Create VPC with the selected VPC offering VPC -> Add new network tier -> verify available network offerings

How did you try to break this feature and the system with this change?