## Description
On desktop, a user can hover over the progress bar while content plays,
which makes it possible to seek to a relatively precise location without
disrupting playback. On mobile there is no hovering, so in order to seek
during inline playback the user can only tap a location on the progress
bar (very hard to do precisely on a small screen) or scrub to try to
hone in on a specific location (can be very clunky because seeks are
constantly being executed). This PR adds a feature to treat scrubbing on
mobile more like hovering on desktop-- while scrubbing, seeks are
disabled and playback continues, only when the user finishes scrubbing
is a single seek executed to the desired location.
One key use-case for this feature is thumbnail seeking integrations on
mobile, where the user can scrub through different thumbnail images
until they find their desired seek location.
## Specific Changes proposed
This behavior is similar to the existing `enableSmoothSeeking` behavior
in that the `PlayProgressBar` slider visibly updates with the scrubbing
movements, but differs in a few ways:
- Playback continues while scrubbing, no seeks are executed until
`touchend`.
- The seek bar's `TimeTooltip` component displays the target seek time
while scrubbing, rather than the `CurrentTimeDisplay` (which continues
to show the current time of the playing content).
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