Fix 2px double border above account panel content in Agents window (#318649)

Fix double 2px border above account panel content

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: eli-w-king <201316543+eli-w-king@users.noreply.github.com>