Replaced nullable fields with non-nullable properties for `Report`
and `BasePdfBytes` to improve initialization and encapsulation.
Updated `OnInitializedAsync` to use `BasePdfBytes` and added
error handling for missing PDF bytes.
Refactored report creation logic by removing `BuildFreshBaseReport`
and `CreateReportInstance`, consolidating functionality into a
new `CreateReport` method. Enhanced `CreateReport` to support
both predefined and dynamically generated reports, simplifying
the code structure and improving maintainability.