Fix text in unit test

Co-authored-by: José Iván López <[email protected]>

service/test/y2storage/agama_proposal_search_test.rb

@@ -207,7 +207,7 @@
             expect(disk.partitions.size).to eq 1
           end
 
-          it "register a no issues about non-existent partitions" do
+          it "does not include any issue about non-existent partitions" do
             proposal.propose
             expect(proposal.issues_list).to be_empty
           end