Fix microbatch behavior flag check (#350)

Author: QMalcolm

.changes/unreleased/Fixes-20241112-141109.yaml

@@ -0,0 +1,6 @@
+kind: Fixes
+body: Negate the check for microbatch behavior flag in determining builtins
+time: 2024-11-12T14:11:09.341634-06:00
+custom:
+  Author: QMalcolm
+  Issue: 349

dbt/adapters/base/impl.py

@@ -1580,8 +1580,14 @@ def valid_incremental_strategies(self):
         return ["append"]
 
     def builtin_incremental_strategies(self):
+        """
+        List of possible builtin strategies for adapters
+
+        Microbatch is added by _default_. It is only not added when the behavior flag
+        `require_batched_execution_for_custom_microbatch_strategy` is True.
+        """
         builtin_strategies = ["append", "delete+insert", "merge", "insert_overwrite"]
-        if self.behavior.require_batched_execution_for_custom_microbatch_strategy.no_warn:
+        if not self.behavior.require_batched_execution_for_custom_microbatch_strategy.no_warn:
             builtin_strategies.append("microbatch")
 
         return builtin_strategies