[Configurator] Need to save twice to generate vUART and IVSHMEM addresses

[amyreye]

Describe the bug

The release v3.0 ACRN Configurator has an issue where you need save the configuration twice to see the generated I/O or BDF address in the vUART setting in the UI. This issue also applies to the BDF address for IVSHMEM. This is purely a UI display issue. It will not cause a data error if the configuration is saved only once.

Codebase
v3.0

To Reproduce for vUART

1. Create shared scenario with one Service VM and one post-launched VM.
2. Create vUART connection, select VMs, select Legacy. Leave I/O address blank.
3. Save the configuration.

Expected: Tool generates I/O address.
Actual: Tool doesn't generate I/O address. User needs to save again, then the tool generates I/O address.

Same issue with PCI and BDF.
Same issue for IVSHMEM.

[amyreye]

[External_System_ID] ACRN-9232