FINERACT-2510: Resolve compilation warnings in fineract-core

[Ambika-Sony]

Description

The details regarding these changes are present on the associated Apache Fineract JIRA ticket.
Summary of work:
Resolved 45 compilation warnings in the fineract-core module,
Replaced deprecated ObjectUtils.defaultIfNull and Date(String) constructor.
Fixed unchecked casts and raw type usage in DataEnricherProcessor and InternalExternalEventService.
Verified the module now compiles cleanly with a "BUILD SUCCESSFUL" status.

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[IOhacker]

Please Squash & Commit

[Ambika-Sony]

Please Squash & Commit

did it