Previously, we would only close the stream when our deliver window was
negative at the circuit-level but _not_ at the stream-level when receiving a
DATA cell.

This commit adds an helper function connection_edge_end_close() which
sends an END and then mark the stream for close for a given reason.

That function is now used both in case the deliver window goes below zero for
both circuit and stream level.

Part of #26840

Signed-off-by: David Goulet <dgoulet@torproject.org>