Enable easier transition to auto-scroll after users submit transcript search

[elynema]

Description

For the initial transcript search implementation, auto-scroll is disabled once a user enters a search term. This is because you can't really page through search results while the transcript is auto-scrolling.

However, this also means that if a user submits a search, and then starts playback, the transcript will not auto-scroll. The user will have to manually clear the search for auto-scroll to be re-enabled.

There may be a better, more intuitive solution for this problem. Could we allow auto-scroll to be re-enabled while media playback is happening? In that case, what would we do if the user submits a transcript search during media playback?

[elynema]

Dananji suggests that we could disable results navigation while media playback is happening. But that could also be confusing to users since they might not know why results navigation is disabled and what to do to get it re-enabled.

[joncameron]

• When disabling autoscrolling, we should un-check the "autoplay" toggle when it is disabled; it indicates that autoscroll is still on and the toggle is disabled, rather than autoscroll itself being disabled.