Fix: prevent type change when using tmp_remove_nodes

[Thijss]

Found was an issue where the graph.external_ids would change type if the input to graph.tmp_remove_nodes is an ndarray[int[ instead of a list[int]

While a type-checker should prevent you from doing this. It is not enforced at runtime.
This PR prevents the type change by explicitly casting the ids to integers before re-adding them to the graph.

Example:

    with graph.tmp_remove_nodes(np.array([1, 2])): 
        pass
# would previously result in graph.external_ids to contain np.int values instead of int values

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[Thijss]

Open question: should we change the type signature of def tmp_remove_nodes(self, nodes: list[int]) -> Generator: to also allow ndarray[int]?
I opted for no so far since we previously settled on keeping everything list[int] within the Graph class

[jaapschoutenalliander]

Well found. On the typing, I think it's cleaner to keep that as it is and just see support for other iterables as a bonus