condA != condB not supported in TSQL

[dataders]

snapshot_check_strategy() is not dispatched, which means it can only be overridden in a custom adapter. Which was working for dbt-sqlserver but we can't import that overwritten macro into dbt-synapse like we're doing with all the other properly dispatched macros.

rather than dispatching the entire snapshot_check_strategy(), we can, with a simple tweak to logic, modify it so that it works on TSQL but doesn't break the existing adapters.

The benefit is a lower code footprint which means the dbt-msft adapters can stay more current with dbt-core