Remove unused member from transport base. Reference counting is done by ReferenceCounted base class. (#1344)
Remove unused member from transport base. Reference counting is done by ReferenceCounted base class. (#1344)

Co-authored-by: Andrei Litvin <bcde013cf8aa18271e342272c256ae8071a48d5d@google.com>
nestlabs/connectedhomeip,nestlabs/connectedhomeip,project-chip/connectedhomeip,nestlabs/connectedhomeip,project-chip/connectedhomeip,project-chip/connectedhomeip,nestlabs/connectedhomeip,nestlabs/connectedhomeip,nestlabs/connectedhomeip,nestlabs/connectedhomeip,project-chip/connectedhomeip,project-chip/connectedhomeip,project-chip/connectedhomeip