fix: updating isMLSCapable (#1905)

* fix: updating isMLSCapable

It should be possible to update isMlsCapable from false to true but not the other
way around.

* chore: add comment explaining update logic for is_mls_capable

persistence/src/commonMain/db_user/com/wire/kalium/persistence/Clients.sq

@@ -42,7 +42,7 @@ model = coalesce(excluded.model, model),
 is_valid = is_valid,
 last_active = coalesce(excluded.last_active, last_active),
 mls_public_keys = excluded.mls_public_keys,
-is_mls_capable = is_mls_capable;
+is_mls_capable = excluded.is_mls_capable OR is_mls_capable; -- it's not possible to remove mls capability once added
 
 selectAllClients:
 SELECT * FROM Client;

persistence/src/commonTest/kotlin/com/wire/kalium/persistence/dao/client/ClientDAOTest.kt

@@ -185,6 +185,32 @@ class ClientDAOTest : BaseDatabaseTest() {
         assertEquals(listOf(client, client2), result)
     }
 
+    @Test
+    fun givenIsMLSCapableIsFalse_whenUpdatingAClient_thenItShouldUpdatedToTrue() = runTest {
+        val user = user
+        userDAO.insertUser(user)
+        clientDAO.insertClient(insertedClient.copy(
+            isMLSCapable = false
+        ))
+        clientDAO.insertClient(insertedClient.copy(
+            isMLSCapable = true
+        ))
+        assertTrue { clientDAO.getClientsOfUserByQualifiedID(userId).first().isMLSCapable }
+    }
+
+    @Test
+    fun givenIsMLSCapableIsTrue_whenUpdatingAClient_thenItShouldRemainTrue() = runTest {
+        val user = user
+        userDAO.insertUser(user)
+        clientDAO.insertClient(insertedClient.copy(
+            isMLSCapable = true
+        ))
+        clientDAO.insertClient(insertedClient.copy(
+            isMLSCapable = false
+        ))
+        assertTrue { clientDAO.getClientsOfUserByQualifiedID(userId).first().isMLSCapable }
+    }
+
     @Test
     fun whenInsertingANewClient_thenIsMustBeMarkedAsValid() = runTest {
         val user = user