feature(symfony): Add CSS Color Schema Restriction for Property Validation

[SebLevDev]

Description

This PR introduces the PropertySchemaCssColorRestriction class, which generates a regular expression (pattern) for validating CSS color values in API Platform property schemas, based on the Symfony CssColor constraint.

Technical Details

Supports multiple CSS color formats (hex, rgb, rgba, hsl, hsla, named colors, etc.). Dynamically builds a single regex pattern combining all allowed formats, suitable for OpenAPI/JSON Schema documentation.