Fix issues with metric conversion and single pump type for filter pumps in Omnilogic integration

[djtimca]

Proposed change

Fixes additional issue with metric conversion for salt-units for Hayward users with their controller set to "Metric".
Fixes issue with SINGLE Speed filter pump types. Should NOT create a sensor for these pump types (will be addressed in Switches platform when released).

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

Example entry for configuration.yaml:

# Example configuration.yaml

Additional information

• This PR fixes or closes issue: fixes Hayward Omnilogic not handling SINGLE pump type #41687
• This PR is related to issue:
• Link to documentation pull request:

Checklist

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

Hey there @Oliver84, @gentoosu, mind taking a look at this pull request as its been labeled with an integration (omnilogic) you are listed as a codeowner for? Thanks!
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[springstan]

Looks good 👍 @djtimca should we tag this for 0.116.3?

[djtimca]

@springstan that would be great as it clears an open issue.