No matter which dashboard you're browsing (an integration's section or a custom dashboard), you can easily add any dashboard to a report.
Add any dashboard to your report
First, head to your client's dashboards tab, and navigate to the required custom dashboard you would like to add. Next, click the Export button at the top right and hit "Add To Report".
Select which report you would like to copy your dashboard to from the drop-down (you can select either an existing report or create a new report to add your dashboard to.)
You'll then receive a "Section Added" confirmation. Your dashboard will be copied to the report as a new report page (also known as a report "section")
You can click "Go To Report" as shown above, to head directly to the report, where you'll see the new section that was created from the dashboard.