feat(roles): Add support for arguments against roles subcommand - #764

What does this PR do?

Adds pagination and filtering support to the pup users roles list command. The command previously called the paginated Datadog list-roles API but exposed no arguments, so callers were stuck with the API defaults and had no way to page through or filter results.

The command now accepts --page-size, --page-number, --sort, --filter, and --filter-id, mapping directly to the five fields on the API's ListRolesOptionalParams.

Motivation

UserRoleActions::List hit a paginated endpoint but had no pagination arguments, unlike sibling commands such as users list and organizations policies list. This meant users could only ever retrieve the first page of roles with no control over sorting or filtering. This change brings the command in line with the rest of the CLI's paginated list commands.

Additional Notes

• Reused the existing RolesSort enum and ListRolesOptionalParams builder from the pinned datadog-api-client-rust crate rather than introducing new types.
• Followed the Option-field conditional-set pattern already used in organizations::policies_list (src/commands/organizations.rs) for consistency.
• --sort accepts the API's documented tokens: name, -name, modified_at, -modified_at, user_count, -user_count. Invalid values return an explicit error.
  This validation lives in a parse_roles_sort helper rather than a clap ValueEnum, matching how organizations.rs handles its sort flag. Happy to switch it to clap-level validation if preferred.

Checklist

• The code change follows the project conventions (see CONTRIBUTING.md)
• Tests have been added/updated (if applicable)
• Documentation has been updated (if applicable)
• All CI checks pass
• Code coverage is maintained or improved

Related Issues

N/A