Add method to dashboards to get dashboard url

[JCZuurmond]

See https://github.com/databrickslabs/ucx/pull/1920#discussion_r1670966525

[github-actions[bot]]

✅ 35/35 passed, 9 flaky, 2 skipped, 15m58s total

Flaky tests:

• 🤪 test_dashboard_deploys_dashboard_with_table (31.167s)
• 🤪 test_dashboard_deploys_dashboard_with_display_name (31.413s)
• 🤪 test_dashboards_deploys_dashboard_with_order_overwrite_in_dashboard_yaml (31.822s)
• 🤪 test_dashboards_deploys_dashboard_with_order_overwrite_in_query_header (33.803s)
• 🤪 test_dashboard_deploys_dashboard_with_empty_title (16.493s)
• 🤪 test_dashboards_deploys_dashboard_with_widget_title_and_description (29.453s)
• 🤪 test_dashboards_deploys_dashboard_with_invalid_query (29.246s)
• 🤪 test_dashboards_deploys_dashboard_from_query_with_cte (30.288s)
• 🤪 test_dashboards_deploys_dashboard_with_markdown_header (32.242s)

_{Running from acceptance #298}