Inconsistent default behaviour for VNet peering in portal and command line

**Related command**
`az network vnet peering create`

**Is your feature request related to a problem? Please describe.**
Default behaviour of az cli to create VNet peering is block access for each VNet, while Azure Portal and Azure PowerShell allow access by default. We should have the same behaviour for default values in portal and command line. this is confusing and error prone.

> Portal
> 
>

> PowerShell (It allows access for each VNet)
> 
> https://learn.microsoft.com/en-us/powershell/module/az.network/add-azvirtualnetworkpeering?view=azps-9.6.0
>

**Describe the solution you'd like**
Default value for parameter of `--allow-vnet-access` to be true.

**Describe alternatives you've considered**
Introduce warning message when customer doesn't pass `--allow-vnet-access` parameter that VMs between each VNet can't connect each other without this parameter.
https://learn.microsoft.com/en-us/cli/azure/network/vnet/peering?view=azure-cli-latest#az-network-vnet-peering-create

**Additional context**
Updating these default values will be breaking changes and may affect existing codes. Then adding warning message might be more feasible workaround than changing default behaviour.