allows merging and unrolling two observations

Runs for #2054 ✅ E2E-test Android app

• 6d6fbea ✔ Run #92843154865 11s on chromium WIP by Gwenn Le Bihan 3 hours ago
• 27ca03a ✔ Run #92157195680 8s on chromium WIP by Gwenn Le Bihan 3 days ago
• 8f5826a ✔ Run #92150777807 8s on chromium WIP by Gwenn Le Bihan 3 days ago
• 0cc47a8 ✔ Run #92146164620 9s on chromium WIP by Gwenn Le Bihan 3 days ago
• 32831ba ✔ Run #92142765729 10s on chromium WIP by Gwenn Le Bihan 3 days ago
• c94dce2 ✔ Run #92135539172 11s on chromium WIP by Gwenn Le Bihan 3 days ago
• 905a9f1 ✔ Run #92127171423 10s on chromium WIP by Gwenn Le Bihan 3 days ago
• 026e164 ✔ Run #92121187264 10s on chromium WIP by Gwenn Le Bihan 3 days ago
• 21ad205 ✔ Run #92001741345 10s on chromium WIP by Gwenn Le Bihan 3 days ago
• f5dae93 ✔ Run #91991793900 9s on chromium WIP by Gwenn Le Bihan 3 days ago
• 89b297a ✔ Run #91844748509 8s on chromium WIP by Gwenn Le Bihan 4 days ago
• 8107142 ✔ Run #91839863559 11s on chromium WIP by Gwenn Le Bihan 4 days ago
• aed4a00 ✔ Run #91837494948 11s on chromium WIP by Gwenn Le Bihan 4 days ago
• 0ada66a ✔ Run #91833261215 10s on chromium WIP by Gwenn Le Bihan 4 days ago