Fix: Simplify detection of adults and children when editing test case.

src/lib/components/test_cases/TestCaseEdit.svelte

@@ -52,13 +52,6 @@
       .map(([name]) => name),
   )
 
-  $: adultsId = [...new Array(countAdults(situation, firstGroupEntity))].map(
-    (_, index) => `Adulte ${index + 1}`,
-  )
-  $: childrenId = [
-    ...new Array(countChildren(situation, firstGroupEntity)),
-  ].map((_, index) => `Enfant ${index + 1}`)
-
   $: persons = Object.entries(
     (situation[personEntity.key_plural] ?? {}) as {
       [id: string]: PopulationWithoutId
@@ -72,6 +65,13 @@
     persons.map((person) => [person.id, person]),
   )
 
+  $: adultsId = [
+    ...Object.keys(personById).filter((id) => id.startsWith("Adulte ")),
+  ]
+  $: childrenId = [
+    ...Object.keys(personById).filter((id) => id.startsWith("Enfant ")),
+  ]
+
   $: yearString = year.toString()
 
   $: updateInputInstantsByVariableName(inputInstantsByVariableName)
@@ -313,12 +313,6 @@
   }
 
   function deletePerson(personId: string): void {
-    const personById = {
-      ...situation[personEntity.key_plural],
-    }
-    delete personById[personId]
-    situation = { ...situation, [personEntity.key_plural]: personById }
-
     for (const groupEntity of Object.values(entityByKey) as GroupEntity[]) {
       if (groupEntity.is_person) {
         continue
@@ -357,6 +351,14 @@
       }
     }
 
+    // Delete person only after it has been removed from all its groups.
+    // To avoid to create a duplicate person.
+    const personById = {
+      ...situation[personEntity.key_plural],
+    }
+    delete personById[personId]
+    situation = { ...situation, [personEntity.key_plural]: personById }
+
     if (
       calculationNames.some(
         (calculationName) => !$requestedCalculationsName.has(calculationName),