[arm-common-types]: percentComplete should be double

### Service Team Contacts (Dev)

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### Choose which kind of change this is

Correction to Existing Type

### Describe the change, Provide the desired TypeSpec or json-schema for the change as appropriate.

In typespec-azure-resource-manager, the type of [percentComplete](https://github.com/Azure/typespec-azure/blob/main/packages/typespec-azure-resource-manager/lib/common-types/types.tsp#L205C3-L205C18) is float64. While in [common types](https://github.com/Azure/azure-rest-api-specs/blob/main/specification/common-types/resource-management/v5/types.json#L447-L452) in swagger repo, we do not specify `"format": "double"` for it.

### Link to documentation if available

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### Additional notes or questions

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### Checklist

- [x] Follow our [Code of Conduct](https://github.com/azure/typespec-azure/blob/main/CODE_OF_CONDUCT.md)
- [x] Change is approved by Arm API Review
- [x] Please update issue title and choose the change type.

Start in packages/typespec-azure-resource-manager/lib/common-types/types.tsp at the percentComplete definition, then compare it with specification/common-types/resource-management/v5/types.json in the linked swagger repository. Update the TypeSpec definition so its generated representation specifies the same double format as the common types schema, and verify the two definitions align.

Written by the indexing model from the issue text.