Found some orphaned transactions added to unexpected transactions

[mrodm]

Relates #1306

While working on #1306 , there were found some orphaned spans that were reparented into unexpected transactions.

Some examples:

This can be reproduced locally by starting an Elastic stack with APM enabled using elastic-package CLI:

elastic-package stack up -v -d -U stack.apm_enabled=true

# Visit https://localhost:5601/app/integrations/browse
# Do some queries to EPR locally 
# curl -s -k "https://localhost:8080/search?all=true
# Check APM overview for package-registry
# https://localhost:5601/app/apm/services/package-registry/overview?comparisonEnabled=true&environment=ENVIRONMENT_ALL&kuery=&latencyAggregationType=avg&offset=1d&rangeFrom=now-15m&rangeTo=now&serviceGroup=&transactionType=request


elastic-package stack down -v

Found a Kibana issue that maybe could be related elastic/kibana#213074