monitoring_dashboard: DashboardFilter proto mismatching with API.

[TenorioStephano]

Package: google-cloud-monitoring-dashboards
Version: 2.22.0

DashboardFilter in this version only exposes label_key, template_variable, string_value, and filter_type:
https://github.com/googleapis/google-cloud-python/blob/google-cloud-monitoring-dashboards-v2.22.0/packages/google-cloud-monitoring-dashboards/google/cloud/monitoring_dashboard_v1/types/dashboard_filter.py

However:

The REST API supports valueType (STRING / STRING_ARRAY) and stringArrayValue for value-only dashboard variables that accept multiple values — documented here: https://docs.cloud.google.com/monitoring/api/ref_v3/rest/v1/projects.dashboards#DashboardFilter

This mismatch means the generated proto/client is behind the actual API surface, and there's no way to construct or parse a STRING_ARRAY-type dashboard filter/variable using the typed Python client — only via raw REST calls.

Is this expected behavior?