copybara-service bot changed the title Refactoring existing strings.cc ext functions into cel-common Enhance core string types with built-in manipulation methods by integrating common string operations, previously in extensions, as methods on the StringValue class.

copybara-service bot changed the title Enhance core string types with built-in manipulation methods by integrating common string operations, previously in extensions, as methods on the StringValue class. Enhance core string types with built-in manipulation methods by integrating common string operations, previously in extensions, as methods in the StringValue class.

…rating common string operations, previously in extensions, as methods in the `StringValue` class.

PiperOrigin-RevId: 831518343