Minor self-hosted video refactor

[domlander]

What does this change?

This is a no-op change.

• We never want to show the progress bar or the icons if the player has yet to begin playing video, so this logic is moved up.
• Logic to update the current time in state when the onTimeUpdate event fires on the video is moved up to the island component.
• When we want to change the time of the video, we usually do two things: update the time on the video itself and update our representation of the current time in state. A helper function that does both has been created.

Why?

• To keep logic in the island instead of the player.
• To keep the code tidy and prepare for upcoming changes.

How to test?

Run storybook locally. Locate the SelfHostedVideo stories

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[SHession]

Changes make sense, I have tested interactions with the player locally. One small functional change, but otherwise LGTM

[SHession]

Small change of behaviour here, although it doesn't seem necessarily worth keeping.

[domlander]

Ah yes, I did explain the reasoning behind this in the PR to implement a new progress bar, but I forgot to move the comment over when I split this PR out: #15726 (comment)

In short, It's an very minor feature that increase the complexity of the code quite a bit when non-looping (default) video is added, so this is why it's removed.

[gu-prout]

Seen on PROD (merged by @domlander 8 minutes and 15 seconds ago) Please check your changes!