chore: uncomment congestion_control.py (near#12021)

After Near-One/nayduck#58, 3 consecutive runs
against master shows that slow_chunk and congestion_control pass now. So
it is safe to uncomment congestion_control.py.

nightly/pytest-sanity.txt

@@ -188,8 +188,7 @@ pytest sanity/slow_chunk.py --features nightly
 pytest sanity/large_witness.py --features nightly
 
 # Tests for congestion control
-# TODO(congestion_control) - enable pytest on stabilization
-# pytest sanity/congestion_control.py
+pytest sanity/congestion_control.py
 pytest sanity/congestion_control.py --features nightly
 pytest sanity/congestion_control_genesis_bootstrap.py
 pytest sanity/congestion_control_genesis_bootstrap.py --features nightly
@@ -204,4 +203,4 @@ pytest sanity/memtrie_disktrie_switch.py --features nightly
 
 # Tests the replay of chain blocks on an archival node.
 pytest sanity/replay_chain_from_archive.py
-pytest sanity/replay_chain_from_archive.py --features nightly
+pytest sanity/replay_chain_from_archive.py --features nightly