libs/pubsub: relax tx querying (#4070)

Some linting/cleanup missed from the initial events refactor
Don't panic; instead, return false, error when matching breaks unexpectedly
Strip non-numeric chars from values when attempting to match against query values
Have the server log during send upon error

* cleanup/lint Query#Conditions and do not panic

* cleanup/lint Query#Matches and do not panic

* cleanup/lint matchValue and do not panic

* rever to panic in Query#Conditions

* linting

* strip alpha chars when attempting to match

* add pending log entries

* Update libs/pubsub/query/query.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* build: update variable names

* update matchValue to return an error

* update Query#Matches to return an error

* update TestMatches

* log error in send

* Fix tests

* Fix TestEmptyQueryMatchesAnything

* fix linting

* Update libs/pubsub/query/query.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* Update libs/pubsub/query/query.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* Update libs/pubsub/query/query.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* Update libs/pubsub/query/query.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* Update libs/pubsub/query/query.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* Update libs/pubsub/pubsub.go

Co-Authored-By: Anton Kaliaev <anton.kalyaev@gmail.com>

* add missing errors pkg import

* update Query#Conditions to return an error

* update query pkg unit tests

* update TxIndex#Search

* update pending changelog

libs/pubsub/query/empty.go

@@ -5,8 +5,8 @@ type Empty struct {
 }
 
 // Matches always returns true.
-func (Empty) Matches(tags map[string][]string) bool {
-	return true
+func (Empty) Matches(tags map[string][]string) (bool, error) {
+	return true, nil
 }
 
 func (Empty) String() string {