Fix all Style/UnneededInterpolation rubocop issues and remove from rubocop_tod

spec/models/budget/investment_spec.rb

@@ -103,7 +103,7 @@ describe Budget::Investment do
     let(:investment) { create(:budget_investment) }
 
       it "returns the proposal id" do
-        expect(investment.code).to include("#{investment.id}")
+        expect(investment.code).to include((investment.id).to_s)
       end
 
       it "returns the administrator id when assigned" do

spec/models/residence_spec.rb

@@ -25,7 +25,7 @@ describe Verification::Residence do
     end
 
     it "should validate user has allowed age" do
-      residence = Verification::Residence.new("date_of_birth(3i)" => "1", "date_of_birth(2i)" => "1", "date_of_birth(1i)" => "#{5.years.ago.year}")
+      residence = Verification::Residence.new("date_of_birth(3i)" => "1", "date_of_birth(2i)" => "1", "date_of_birth(1i)" => (5.years.ago.year).to_s)
       expect(residence).to_not be_valid
       expect(residence.errors[:date_of_birth]).to include("You don't have the required age to participate")
     end

spec/models/spending_proposal_spec.rb

@@ -136,7 +136,7 @@ describe SpendingProposal do
       let(:spending_proposal) { create(:spending_proposal) }
 
       it "returns the proposal id" do
-        expect(spending_proposal.code).to include("#{spending_proposal.id}")
+        expect(spending_proposal.code).to include((spending_proposal.id).to_s)
       end
 
       it "returns the administrator id when assigned" do