fix(desktop): scroll activity panel to bottom on open (#848)

Signed-off-by: Wes <wesbillman@users.noreply.github.com>
Co-authored-by: Brain <21994759fc7a6fa6b965551d35cfd7897d262f2495467f2d78694ddcfa6a5c7e@sprout-oss.stage.blox.sqprod.co>

desktop/src/shared/hooks/useStickToBottom.ts

@@ -27,6 +27,9 @@ export function useStickToBottom<T extends HTMLElement = HTMLDivElement>() {
     const el = ref.current;
     if (!el) return;
 
+    // Start at the bottom; the observer below only reacts to later changes.
+    el.scrollTop = el.scrollHeight;
+
     let rafId: number | null = null;
 
     const scrollIfSticky = () => {