VMSize not recognised when it's in a variable (possible regression of #695)

The following Bicep;

`
var referenceImage = {
windows: {
publisher: 'MicrosoftWindowsServer'
offer: 'WindowsServer'
sku: '2019-Datacenter'
version: 'latest'
VMsize: 'Standard_D4s_v3'
}
}

.
.
.

resource ImageReferenceVM 'Microsoft.Compute/virtualMachines@2022-08-01' = {
name: 'prdaueimagevm01'
location: location
properties: {
hardwareProfile: {
vmSize: referenceImage.windows.VMsize
}
osProfile: {
computerName: 'prdaueimagevm01'
adminUsername: vmAdminUsername
adminPassword: vmAdminPassword
}
storageProfile: {
imageReference: {
publisher: referenceImage.windows.publisher
offer: referenceImage.windows.offer
sku: referenceImage.windows.sku
version: referenceImage.windows.version
}
osDisk: {
createOption: 'FromImage'
managedDisk: {
storageAccountType: 'StandardSSD_LRS'
}

`

Raises an error with the latest arm-ttk (0.22) that

_VM Size for resourceType ' ' named ' ' must be a parameter_

Start by reproducing the reported ARM-TTK 0.22 validation error with the Bicep example, focusing on the VMSize value supplied through referenceImage.windows.VMsize. Trace the VM size validation entry point and its existing tests. Done means a VM size held in a variable is recognised without the erroneous parameter-required message, while direct values remain validated.

Written by the indexing model from the issue text.