Revert "PT-45056929 - Add back support agent dial strings in openacd"

This reverts commit f7a87e9fc14fd3a1e61e3128d4261ba8fee9c7e2.
Revert "PT-45056929 - Add back support agent dial strings in openacd"

This reverts commit 2fa8de1bd154ec48da7cc5b63da55010e9be1d3c.