fix: ledger_data returns an empty list (instead of null) when all entries are filtered out

[drlongle]

High Level Overview of Change

This PR resolves issue 4392. When the type field to the ledger_data method is specified, it is possible that no objects of the specified type are found. When this happens, the state field of the response has the value null instead of an empty array ([]).

Context of Change

The PR initializes the state field of the response to an empty list so that the field is not a null. This can break client code that explicitly checks for null. However, this behavior is consistent with the documentation.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Refactor (non-breaking change that only restructures code)
• Tests (You added tests for code that already exists, or your new feature included in this PR)
• Documentation Updates
• Release

[intelliot]

@drlongle if you agree that this is ready to merge, please comment with a suggested commit message for this PR

[drlongle]

Suggested commit message

When no entries are found, make ledger_data return an empty array instead of null: (#4392)

When the type field for the ledger_data method is specified, it is possible that no objects of the specified type are found. When this happens, the state field of the response has the value null instead of an empty array. According to the documentation, the state field should be an array.