Set PARALLEL_UPDATES for MotionMount integration

[RJPoelstra]

Proposed change

This PR sets the PARALLEL_UPDATES for the entities.

Most entities are updated using push model and are not actively updated by HA. The select sensor does perform a (slow) poll, but as there is only a single device per sensor we can allow multiple updates at the same time as they will be directed to different devices.

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)
• Deprecation (breaking change to happen in the future)
• 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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