Save scroll position

**Describe the bug**
After the chat activity dies, the scroll position isn't saved on relaunch

**To Reproduce**
Steps to reproduce the behavior:
1. Open some popular chat channel like wallstreetbets
2. Scroll up for a while so you're not at the latest message
2. Leave the app for a bit or turn on don't save activities in developer options
3. Come back to the app
4. Observe that the chat is scrolled back to the bottom again

**Expected behavior**
Would be nice to keep the previous scroll position if you're trying to read things sequentially from a position and want to keep reading after taking a break.

**Smartphone (please complete the following information):**
- Device: Huawei Mate 40 Pro Plus
- OS: Android 10

**Additional context**
- 1.0.14
- Homeserver: home.xster.net

Add any other context about the problem here.