[DAT-15383] Fix checksum upgrade changes preventing useless updates and using AbstractChangeLogHistoryService for extensions compatibility

[filipelautert]

Impact

• Bug fix (non-breaking change which fixes expected existing functionality)
• Enhancement/New feature (adds functionality without impacting existing logic)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

New method liquibase.changelog.visitor.UpdateVisitor#updateCheckSumIfRequired returns null if the change set has a stored checkSum, but it should return the old checksum value.
So everytime we get here we are updating the checksums for already executed checksums with the same value. It's not breaking anything but performance will be affected.

Steps To Reproduce
Run update using a changelog with 1 changeset
Add a new changeset to changelog
Run update SQL: first changelog will have the checksum updated and the second will execute just fine.
ex:

UPDATE public.databasechangelog SET MD5SUM = '9:56da2f293105bdbf802515b0581600f1' WHERE ID = '2' AND AUTHOR = 'fl' AND FILENAME = 'changelogs/changelog/simple_changelog.xml';

INSERT INTO public.databasechangelog (ID, AUTHOR, FILENAME, DATEEXECUTED, ORDEREXECUTED, MD5SUM, DESCRIPTION, COMMENTS, EXECTYPE, CONTEXTS, LABELS, LIQUIBASE, DEPLOYMENT_ID, TAG) VALUES ('2.5', 'fl', 'changelogs/changelog/simple_changelog.xml', NOW(), 4, '9:9a2f4bc8afbf0c9587b25b2ffd922d2e', 'tagDatabase', '', 'EXECUTED', 'v8', NULL, 'DEV', '7973169078', 'rb1');