* agent sessions - add a view filter action to filter by provider type

* Update src/vs/workbench/contrib/chat/browser/agentSessions/agentSessionsViewFilter.ts

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* feedback

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>