When I try to pin a chart through Log Analytics Workspace it says "Pin to Dashboard is not supported in this environment". It was working fine 3 days ago. I have changed no accounts, not subscriptions as everything is the same. It is blurred out and when you hover over it, it gives the error message "Pin to Dashboard is not supported in this environment"
It might be due to some changes, and will be fixed later.
At the meantime, you can try to use Azure Monitor Workbooks, which can also be used to write query and pin to dashboard.