Do not register jdbc-driver's datasource-class-info as metric

jdbc-driver resource registers 1 attribute as metric:

• datasource-class-info

/subsystem=datasources/jdbc-driver=h2:read-attribute(name=datasource-class-info)
{
    "outcome" => "success",
    "result" => [{"org.h2.jdbcx.JdbcDataSource" => {
        "URL" => "java.lang.String",
        "description" => "java.lang.String",
        "loginTimeout" => "int",
        "password" => "java.lang.String",
        "url" => "java.lang.String",
        "user" => "java.lang.String"
    }}]
}

This attribute is not an actual metric (that may change due to server activity).
It should be registered as runtime read-only attributes instead.

This change only impacts metadata and does not require resource transformation.

Additionally, I've checked with HAL team that this change has no impact on HAL UI (that does not distinguish between read-only runtime attribute and metric).