Dashboard crashes when Proposals are deleted

Culprit: Admin Log (rendered in the Dashboard and in the Admin Activity Log). The problem is that proposal drafts can be removed, but the Admin Activity Log, when renders Proposals takes for granted that the associated resource, when a Proposal, there's always there. But this is not always true. The crash raises in Decidim::Proposals::ProposalPresenter.title:L44 with the typical "no title method for Nil class" message.