Rename unfinished trait to open

So now it's more consistent with the name we use in the rest of the
code.

spec/factories/budgets.rb

@@ -121,7 +121,7 @@ FactoryBot.define do
       valuation_finished { true }
     end
 
-    trait :unfinished do
+    trait :open do
       valuation_finished { false }
     end
 

spec/features/admin/budget_investments_spec.rb

@@ -334,7 +334,7 @@ describe "Admin budget investments" do
       valuator = create(:valuator, user: user)
       create(:budget_investment,
         :with_administrator,
-        :unfinished,
+        :open,
         title: "Investment without valuation",
         budget: budget,
         valuators: [valuator])

spec/features/budgets/investments_spec.rb

@@ -1259,7 +1259,7 @@ describe "Budget Investments" do
   scenario "Show (unfeasible budget investment with valuation not finished)" do
     investment = create(:budget_investment,
                         :unfeasible,
-                        :unfinished,
+                        :open,
                         budget: budget,
                         heading: heading,
                         unfeasibility_explanation: "Local government is not competent in this matter")

spec/models/budget/investment_spec.rb

@@ -1152,7 +1152,7 @@ describe Budget::Investment do
     describe "with under_valuation filter" do
       let(:params) { { advanced_filters: ["under_valuation"], budget_id: budget.id } }
       it "returns only investment under valuation" do
-        investment1 = create(:budget_investment, :with_administrator, :unfinished, :with_valuator,
+        investment1 = create(:budget_investment, :with_administrator, :open, :with_valuator,
                              budget: budget)
         create(:budget_investment, :with_administrator, budget: budget)
         create(:budget_investment, budget: budget)