There is no need to check that the `ref.node` is of any particular type
because immediately after this check the entry is tested to see if it passes
`isClassDeclarationReference()`.
The only difference is that the error that is reported is slightly different
in the case that it is a `ref` but not one of the TS node types.
Previously:
```
`Value at position ${idx} in the NgModule.${arrayName} of ${
className} is not a reference`
```
now
```
`Value at position ${idx} in the NgModule.${arrayName} of ${
className} is not a class`
```
Arguably the previous message was wrong, since this entry IS a reference
but is not a class.
PR Close#38959
f35e9158b2