Fix standalone SQLite exclusion filters

[Old-Ding]

Summary

• avoid leading commas when SQLite exclusion filters contain service events but no ordinary topics
• apply the same delimiter rule when action interfaces are the first populated exclusion list
• add real SQLite storage coverage for service-only and action-only blacklists

Testing

• reproduced the generated NOT IN (,'...') query failing with near ,: syntax error in native SQLite
• verified corrected service-only and action-only NOT IN ('...') queries execute successfully and remove only the requested item
• verified both regression cases read nine of the ten fixture topics and omit the selected service/action interface
• UTF-8 without BOM and CRLF checks
• 100-column check
• git diff --check

The repository-native C++ test was not run locally because this Windows environment does not have the ROS 2 build dependencies or colcon. Repository CI covers the SQLite storage test.