Remove some unreachable error handling
Remove some unreachable error handling

We validate that the property type is indexable long before trying to index the
column, so it is not actually possible to hit the unindexable column error.

realm/realm-core,realm/realm-core,realm/realm-core,realm/realm-object-store,realm/realm-object-store,realm/realm-core,realm/realm-object-store,realm/realm-core,realm/realm-core,realm/realm-core