Fix triage delay not being created for invalid MMR doses

When an invalid MMR dose is recorded (given too early), the triage
delay for the next dose was not being created. This occurred because the
`NextDoseTriageFactory` incorrectly assumed that if a patient reached the
maximum dose sequence (2 for MMR), no further triage was required.

This change ensures that a 28-day delay triage is created if the patient
is not yet considered fully vaccinated, regardless of the current dose
sequence count. This adheres to clinical guidance that the 28-day
interval should reset from the most recent dose even if that dose was
invalid.

Author: jhenderson

app/lib/next_dose_triage_factory.rb

@@ -32,10 +32,9 @@ def should_create?
 
     return false if next_date.past?
 
-    dose_sequence =
-      patient.vaccination_status(programme:, academic_year:).dose_sequence
+    status = patient.vaccination_status(programme:, academic_year:)
 
-    dose_sequence != programme.maximum_dose_sequence
+    !status.vaccinated?
   end
 
   def next_date = vaccination_record.performed_at + 28.days

spec/lib/next_dose_triage_factory_spec.rb

@@ -37,5 +37,37 @@
         expect { call }.not_to(change(Triage, :count))
       end
     end
+
+    context "when it is an invalid second MMR dose (too early)" do
+      let(:patient) do
+        create(
+          :patient,
+          :consent_given_triage_safe_to_vaccinate,
+          year_group: 9,
+          session:
+        )
+      end
+      let(:session) { create(:session, programmes: [programme]) }
+
+      it "shows delay vaccination 28 days after last vaccine" do
+        create(
+          :vaccination_record,
+          programme:,
+          patient:,
+          session:,
+          performed_at: 20.days.ago
+        )
+        second_dose =
+          create(:vaccination_record, programme:, session:, patient:)
+
+        StatusUpdater.call(patient:)
+
+        described_class.call(vaccination_record: second_dose.reload)
+
+        triage = second_dose.reload.next_dose_delay_triage
+
+        expect(triage.delay_vaccination_until).to eq(28.days.from_now.to_date)
+      end
+    end
   end
 end