refactor: Unify severity and level for all application errors for Sentry (no-changelog) (#7956)

## Summary
Unify `severity` and `level` for all backend application errors for
Sentry

Follow-up to:
https://github.com/n8n-io/n8n/pull/7914#issuecomment-1840433542

...

#### How to test the change:
1. ...


## Issues fixed
Include links to Github issue or Community forum post or **Linear
ticket**:
> Important in order to close automatically and provide context to
reviewers

...


## Review / Merge checklist
- [ ] PR title and summary are descriptive. **Remember, the title
automatically goes into the changelog. Use `(no-changelog)` otherwise.**
([conventions](https://github.com/n8n-io/n8n/blob/master/.github/pull_request_title_conventions.md))
- [ ] [Docs updated](https://github.com/n8n-io/n8n-docs) or follow-up
ticket created.
- [ ] Tests included.
> A bug is not considered fixed, unless a test is added to prevent it
from happening again. A feature is not complete without tests.
  >
> *(internal)* You can use Slack commands to trigger [e2e
tests](https://www.notion.so/n8n/How-to-use-Test-Instances-d65f49dfc51f441ea44367fb6f67eb0a?pvs=4#a39f9e5ba64a48b58a71d81c837e8227)
or [deploy test
instance](https://www.notion.so/n8n/How-to-use-Test-Instances-d65f49dfc51f441ea44367fb6f67eb0a?pvs=4#f6a177d32bde4b57ae2da0b8e454bfce)
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packages/cli/src/ErrorReporting.ts

@@ -1,6 +1,6 @@
 import { createHash } from 'crypto';
 import config from '@/config';
-import { ErrorReporterProxy, ApplicationError, ExecutionBaseError } from 'n8n-workflow';
+import { ErrorReporterProxy, ApplicationError } from 'n8n-workflow';
 
 let initialized = false;
 
@@ -39,9 +39,6 @@ export const initErrorHandling = async () => {
 
 	const seenErrors = new Set<string>();
 	addGlobalEventProcessor((event, { originalException }) => {
-		if (originalException instanceof ExecutionBaseError && originalException.severity === 'warning')
-			return null;
-
 		if (originalException instanceof ApplicationError) {
 			const { level, extra } = originalException;
 			if (level === 'warning') return null;

packages/cli/src/UserManagement/PermissionChecker.ts

@@ -72,7 +72,7 @@ export class PermissionChecker {
 
 		throw new NodeOperationError(nodeToFlag, 'Node has no access to credential', {
 			description: 'Please recreate the credential or ask its owner to share it with you.',
-			severity: 'warning',
+			level: 'warning',
 		});
 	}
 
@@ -151,7 +151,7 @@ export class PermissionChecker {
 					if (!cred.id) {
 						throw new NodeOperationError(node, 'Node uses invalid credential', {
 							description: 'Please recreate the credential.',
-							severity: 'warning',
+							level: 'warning',
 						});
 					}
 

packages/cli/src/errors/credential-not-found.error.ts

@@ -1,10 +1,8 @@
-import { ApplicationError, type Severity } from 'n8n-workflow';
+import { ApplicationError } from 'n8n-workflow';
 
 export class CredentialNotFoundError extends ApplicationError {
-	severity: Severity;
-
 	constructor(credentialId: string, credentialType: string) {
 		super(`Credential with ID "${credentialId}" does not exist for type "${credentialType}".`);
-		this.severity = 'warning';
+		this.level = 'warning';
 	}
 }