support non-newline-terminated ignore-list files (#3404)

Fixes DACH-NY/cn-test-failures#6660.

before this change:
$ cat project/ignore-patterns/canton-standalone-sv4-reonboarding-new.ignore.txt | remove_comment_and_blank_lines
ACS_COMMITMENT_MISMATCH

after this change:
$ cat project/ignore-patterns/canton-standalone-sv4-reonboarding-new.ignore.txt | remove_comment_and_blank_lines
ACS_COMMITMENT_MISMATCH
'sequencer-client' is now in state Failed.*The sequencer client's healthy subscriptions count is under the configured BFT threshold.*

* remove "Make sure to have a trailing newline" notes

---------

Signed-off-by: Stephen Compall <stephen.compall@digitalasset.com>

Author: stephencompall-DA

.github/actions/scripts/io-utils.sh

@@ -11,7 +11,7 @@
 
 # Copy stdin to stdout, while removing all lines that start with '#' or consist of blanks
 remove_comment_and_blank_lines() {
-  while IFS= read -r # Read a file line by line; IFS= ensures that no separators other than newline are used
+  while IFS= read -r || [[ -n $REPLY ]] # Read a file line by line; IFS= ensures that no separators other than newline are used
   do
     if [[ -n "${REPLY// }" ]] && [[ "$REPLY" != "#"* ]] # Filter out comment lines and blank lines
     then

project/ignore-patterns/canton-standalone-disaster-recovery-lost-all-sequencers-most-participants.ignore.txt

@@ -7,5 +7,3 @@ Using approximate topology snapshot.*.*StandaloneSequencer
 Failed to acknowledge clean timestamp.*closed stream
 
 The traffic balance request submission timed
-
-# Make sure to have a trailing newline

project/ignore-patterns/canton-standalone-disaster-recovery-lost-domain.ignore.txt

@@ -7,5 +7,3 @@ Using approximate topology snapshot.*.*StandaloneSequencer
 Response message for request.*timed out
 
 The traffic balance request submission timed
-
-# Make sure to have a trailing newline

project/ignore-patterns/canton-standalone-participants-before-disaster-lost-all-sequencers-most-participants.ignore.txt

@@ -7,5 +7,3 @@ SEQUENCER_SUBSCRIPTION_LOST
 Failed to acknowledge clean timestamp.*closed stream
 
 'sequencer-client' is now in state Failed
-
-# Make sure to have a trailing newline

project/ignore-patterns/canton-standalone-participants-before-disaster-lost-domain.ignore.txt

@@ -7,5 +7,3 @@ SEQUENCER_SUBSCRIPTION_LOST
 Failed to acknowledge clean timestamp.*CANCELLED
 
 'sequencer-client' is now in state Failed
-
-# Make sure to have a trailing newline

project/ignore-patterns/canton_log.ignore.txt

@@ -165,5 +165,3 @@ Dynamic synchronizer parameters to compute earliest available pruning timestamp
 
 # TODO(#3193): Likely a race in the shutdown of the actor system vs us scheduling something else on it
 java.lang.IllegalStateException: cannot enqueue after timer shutdown
-
-# Make sure to have a trailing newline

project/ignore-patterns/canton_log_shutdown_extra.ignore.txt

@@ -30,5 +30,3 @@ Trying to materialize stream after materializer has been shutdown
 ApiUpdateService.*AbruptTerminationException
 # Consequence of the AbruptTerminationException
 UpdateService/GetUpdates.*failed with INTERNAL
-
-# Make sure to have a trailing newline

project/ignore-patterns/canton_log_simtime_extra.ignore.txt

@@ -35,5 +35,3 @@ Request failed for sequencer.*GrpcServiceUnavailable: UNAVAILABLE/Health-check s
 # This kicks in when an interval is skipped which can easily be caused in simtime mode
 # by bumping the time by more than the reconciliation interval.
 ACS_COMMITMENT_DEGRADATION
-
-# Make sure to have a trailing newline

project/ignore-patterns/canton_network_test_log.ignore.txt

@@ -132,5 +132,3 @@ Circuit breaker .* tripped after .* failures.*(Command|Splice)CircuitBreakerTest
 # See DACH-NY/cn-test-failures#6328: In rare cases, creating an index asynchronously can fail.
 # This is more likely in test code where we run multiple apps against the same database, all trying to create the same index.
 Index .* should be created and is invalid, dropping it
-
-# Make sure to have a trailing newline

project/ignore-patterns/sbt-output.ignore.txt

@@ -128,5 +128,3 @@ Retried waiting for GCLocker too often allocating
 canton/base/errors
 
 Cannot use file /tmp/hsperfdata_ci
-
-# Make sure to have a trailing newline