Fixes #3218: java.lang.NullPointerException when setting the type of a property to datetime in the mapping config of apoc.load.csv()

[vga91]

Fixes #3218

• Waiting for APOC Core PR: [mMXNEtoY] Add default value for optionalData. neo4j/apoc#571

Up to 5.16 we had to use a workaround not to throw a NullPointerException with datetime/time mappings, since the bug is in Core.
E.g.

CALL apoc.load.csv('test.csv', {mapping:{name:{type: "datetime", optionalData: {}}}})

But, as this PR neo4j/apoc#571 is merged,
we can use datetime without optionalData: {} workaround, e.g.:

CALL apoc.load.csv('test.csv', {mapping:{name:{type: "datetime"}}})

Changes:

• added test with multiple types and optionalData
• added test with multiple types and without optionalData, to check that the APOC Core's fix works correctly
• added assertMapEquals util, to check more easily the possible failied entry map