Lambdas do not support resource references

@anthony-c-martin I could not find the documentation for the new function features published yet but there are examples here in this PR. However for one of the main reasons to have index for lambda functions was to be able to access resource arrays and I have found out that this is not possible. Any idea why this was not done? It seems only half of the job was done.

```
properties: {
actionGroups: map(eventSubscription.destination.actionGroups, (actionGroup, i) => actionGroups[i].id)
}
```

shows error:

```

Using lambda variables inside resource or module array access is not currently supported. Found the following lambda variable(s) being accessed: "i".bicep(BCP247)

```

_Originally posted by @slavizh in https://github.com/Azure/bicep/issues/13658#issuecomment-2117258414_