Move key sequences to bridge in SamsungTV

[epenet]

Proposed change

Currently, key sequences are handled inside media_player, with a sleep in between each key.
However, this timer is also already part of the websocket library, so it should be kept only for the legacy bridge.

Note: currently, only async_play_media uses key sequences (eg. 5 + 7 + 6 + ENTER to set channel 576) but new sequences will be added in the future.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
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Checklist

• The code change is tested and works locally.
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[probot-home-assistant]

Hey there @escoand, @chemelli74, mind taking a look at this pull request as it has been labeled with an integration (samsungtv) you are listed as a code owner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[bdraco]

I'm traveling so I can't test until next week.

[bdraco]

Updated my instance remotely and tested. Couldn't verify in person, but it seems to work as expected. Will do manual testing later this week and message on discord if I find an issue.