Artifact retrieval failure logs at info level

[damccorm]

This should log at at least the warning level.

beam/runners/java-fn-execution/src/main/java/org/apache/beam/runners/fnexecution/artifact/AbstractArtifactRetrievalService.java

Line 170 in 94c6d8d

LOG.info("GetArtifact {} failed", request, e);

Imported from Jira BEAM-8899. Original Jira may contain additional context.
Reported by: ibzib.