Fix unused import warnings

dagger/blockexchange/engine.nim

@@ -8,7 +8,6 @@
 ## those terms.
 
 import std/sequtils
-import std/algorithm
 
 import pkg/chronos
 import pkg/chronicles

tests/dagger/testblockexc.nim

@@ -3,3 +3,5 @@ import ./blockexc/testnetwork
 import ./blockexc/protobuf/testpayments as testprotobufpayments
 import ./blockexc/protobuf/testpresence
 import ./blockexc/engine/testpayments as testenginepayments
+
+{.warning[UnusedImport]: off.}

tests/dagger/testblockset.nim

@@ -1,4 +1,3 @@
-
 import pkg/chronos
 import pkg/questionable
 import pkg/questionable/results
@@ -7,7 +6,6 @@ import pkg/libp2p
 import pkg/stew/byteutils as stew
 
 import pkg/dagger/chunker
-import pkg/dagger/rng
 import pkg/dagger/blocktype as bt
 import pkg/dagger/blockstream
 import pkg/dagger/blockset

tests/dagger/teststores.nim

@@ -1,2 +1,4 @@
 import ./stores/testblockexc
 import ./stores/testblockstore
+
+{.warning[UnusedImport]: off.}