Revert "Set volume_step in bluesound media_player"

[emontnemery]

Reverts #105672

There was some additional issues brought up in home-assistant/architecture#1012 after this PR was merged. This functionality needs to be reverted until they way forward is clear.

[home-assistant]

Hey there @thrawnarn, mind taking a look at this pull request as it has been labeled with an integration (bluesound) you are listed as a code owner for? Thanks!

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