### Body

We had an issue where extra link class (`AIPlatformConsoleLink`) was removed in [PR](https://github.com/apache/airflow/pull/26836) without removing the class from the `provider.yaml` extra links this resulted in web server exception as shown in https://github.com/apache/airflow/pull/28449


**The Task:**
Add validation that classes of extra-links in provider.yaml are importable

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.
netloc = host
            else:
                netloc = ""
        return urlunsplit((url_parts.scheme, netloc, url_parts.path, url_parts.query, url_parts.fragment))
class OperatingSystem:
    """Operating system."""
    WINDOWS = "Windows"
    LINUX = "Linux"
    MACOSX = "Mac OS"
    CYGWIN = "Cygwin"
    @staticmethod
    def get_current() -> str | None:
        """Get current operating system."""
        if os.name == "nt":
            return OperatingSystem.WINDOWS
        elif "linux" in sys.platform:
            return OperatingSystem.LINUX
        elif "darwin" in sys.platform:
            return OperatingSystem.MACOSX
        elif "cygwin" in sys.platform:
            return OperatingSystem.CYGWIN
        return None
class Architecture:
    """Compute architecture."""
    X86_64 = "x86_64"
    X86 = "x86"
    PPC = "ppc"
    ARM = "arm"
    @staticmethod
    def get_current():