Fix: slices homepage metrics count

[syphax-bouazzouni]

fix #762

Example of crop slice

Compared to the not sliced metrics

[Bilelkihal]

@syphax-bouazzouni It's not working (even for the ontologies number).
To test it locally, enable slices in the config file and enter to the slice using a link like inrae.localhost:3000.
(It's better to use AgroPortal api)

[Bilelkihal]

@syphax-bouazzouni

• The metrics that are correct are: ontologies, classes, individuals and properties
• The metrics that still doesn't change whether we choose a slice or no are: projects and mappings

[syphax-bouazzouni]

Fixed the remaining metrics to filter.

[Bilelkihal]

@syphax-bouazzouni, good job. I confirm that it's working correctly.