Chapter seeking is inconsistent and inaccurate

### Description

When playing back a podcast episode with chapters, the playback position is sometimes off by a few seconds from where it should be. For example, sometimes tapping a chapter will start playback a few seconds before the end of a previous chapter, and sometimes it will start a few seconds into the selected chapter.

It should be expected that chapter playback starts at a consistent and accurate position.

### Step-by-step reproduction instructions

Note: though there have been related issues with dynamic ads, this also occurs with podcast episodes that have no ads.

1. Start playing an episode which has chapters
2. Select the chapters tab from the top bar
3. Tap around various chapters (jump around between chapters, forward and backward a few times)
4. 💥 Observe that sometimes the playback position for a given chapter is not always correct nor consistent

### Screenshots or screen recording

Screen recording found on this ticket: 8479318-zd-a8c

### Did you search for existing bug reports?

- [X] I have searched for existing bug reports.

### Device, Operating system, and Pocket Casts app version

Pixel 3a, Android 12, Pocket Casts version 7.67

The issue names no source files or tests. Reproduce on Android 12 with Pocket Casts 7.67 using an episode with chapters, then trace the chapter-selection seeking path and compare repeated forward and backward jumps with chapter timestamps. Done means each selected chapter starts consistently and accurately, including episodes without dynamic ads.

Written by the indexing model from the issue text.