Timeline tweaks (#10693)

* make segment height static

* fix timeline overscrolling

* better alignment of motion timeline segments

web/src/hooks/use-camera-activity.ts

@@ -82,7 +82,7 @@ export function useCameraMotionNextTimestamp(
   });
 
   const noMotionRanges = useMemo(() => {
-    if (!motionData || !reviewItems) {
+    if (!motionData || !reviewItems || !motionData) {
       return;
     }
 
@@ -100,8 +100,7 @@ export function useCameraMotionNextTimestamp(
         alignStartDateToTimeline(timeRangeSegmentEnd)) %
       segmentDuration;
 
-    const startIndex =
-      offset > 0 ? Math.floor(offset / (segmentDuration / 15)) : 0;
+    const startIndex = Math.abs(Math.floor(offset / 15));
 
     for (
       let i = startIndex;