perf: bulk action import caching (#41807)

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Fixes #`Issue Number`  
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Fixes `Issue URL`
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## Automation

/ok-to-test tags="@tag.ImportExport, @tag.Git"

### 🔍 Cypress test results
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> [!TIP]
> 🟢 🟢 🟢 All cypress tests have passed! 🎉 🎉 🎉
> Workflow run:
<https://github.com/appsmithorg/appsmith/actions/runs/25814789299>
> Commit: 1fc6461
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> Tags: `@tag.ImportExport, @tag.Git`
> Spec:
> <hr>Wed, 13 May 2026 17:37:04 UTC
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## Communication
Should the DevRel and Marketing teams inform users about this change?
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- [ ] No


<!-- This is an auto-generated comment: release notes by coderabbit.ai
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## Summary by CodeRabbit

* **New Features**
* Added bulk action validation support for imports with dry-run mode
capability.
* Enhanced import pipeline with improved datasource policy and plugin
metadata handling.

* **Tests**
* Added validation tests for import scenarios, including public
datasource policy updates and dry-run validation modes.

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Author: sondermanish

app/server/appsmith-server/src/main/java/com/appsmith/server/newactions/base/NewActionServiceCE.java

@@ -36,10 +36,15 @@ public interface NewActionServiceCE extends CrudService<NewAction, String> {
 
     Mono<NewAction> validateAction(NewAction newAction, boolean isDryOps);
 
+    Mono<Tuple2<List<NewAction>, List<NewAction>>> validateActionsBeforeImport(
+            String artifactId, List<NewAction> freshActions, List<NewAction> existingActions);
+
     Mono<Void> bulkValidateAndInsertActionInRepository(List<NewAction> newActionList);
 
     Mono<Void> bulkValidateAndUpdateActionInRepository(List<NewAction> newActionList);
 
+    Mono<Void> bulkInsertActions(List<NewAction> newActionList);
+
     /**
      * General purpose bulk update method that directly saves actions to the database without validation.
      * This method is optimized for scenarios where the actions are already validated or when