Increase coverage org.kie.workbench.common.dmn.client.editors.expressions.types.literal

The actual coverage form the attachment should be increased.

• LiteralExpressionGrid - just factory method calls
• LiteralExpressionColumnRenderer - https://github.com/kiegroup/kie-wb-common/pull/1347
• LiteralExpressionUIModelMapper - https://github.com/kiegroup/kie-wb-common/pull/1346
• LiteralExpressionEditorDefinition - just getters and setters
• LiteralExpressionColumnHeaderMetaData - just extends another class
• LiteralExpressionGridRenderer - just extends another class