chore: Add total doctors count to hospital doctor list response

care/facility/api/serializers/hospital_doctor.py

@@ -1,4 +1,5 @@
 from rest_framework import serializers
+from django.db.models import Sum
 
 from care.facility.api.serializers import TIMESTAMP_FIELDS
 from care.facility.models import DOCTOR_TYPES, HospitalDoctors
@@ -8,11 +9,25 @@
 class HospitalDoctorSerializer(serializers.ModelSerializer):
     area_text = ChoiceField(choices=DOCTOR_TYPES, read_only=True, source="area")
     id = serializers.UUIDField(source="external_id", read_only=True)
+    total_doctors = serializers.IntegerField(read_only=True)
 
     class Meta:
         model = HospitalDoctors
         read_only_fields = (
             "id",
             "area_text",
+            "total_doctors"
         )
         exclude = (*TIMESTAMP_FIELDS, "facility", "external_id")
+
+    def to_representation(self, instance):
+        representation = super().to_representation(instance)
+        try:
+            representation["total_doctors"] = (
+                HospitalDoctors.objects.filter(facility=instance.facility)
+                .aggregate(total_doctors=Sum("count"))["total_doctors"]
+                or 0
+            )
+        except Exception as e:
+            representation["total_doctors"] = 0
+        return representation