Fix/misc

[TDannhauer]

Summary

Fix PHP warnings from missing optional Horde data and restore default log timestamps:

• Treat missing prefGroups and _prefs entries as empty arrays when loading app preferences.
• Make ActiveSync email change handling tolerate missing category data and skip modified UIDs without flag data.
• Restore the default logger formatter so standard log output includes timestamp and level again.

Why

Some apps or config states may not define preference groups, and some ActiveSync IMAP change sets can include UIDs without complete flag/category metadata. These cases should not produce PHP Undefined array key warnings during normal operation.

The default PSR logger path was using a message-only formatter, which dropped the timestamp and log level from file logs. Using the default SimpleFormatter matches the legacy Horde log format.

Test Plan

• Ran php -l on:
  • vendor/horde/core/lib/Horde/Core/Prefs/Ui.php
  • vendor/horde/core/lib/Horde/Core/ActiveSync/Driver.php
  • vendor/horde/core/src/Factory/LogHandlerFactory.php
• Verified no syntax errors.
• Smoke-tested default log formatting includes timestamp and level.