ci: Fix lint warnings in @n8n/chat and @n8n/nodes-langchain (no-changelog) (#7884)

Solve lint warnings shown on all PRs for `@n8n/chat` and
`@n8n/nodes-langchain`

Example: https://github.com/n8n-io/n8n/pull/7883/files

packages/@n8n/chat/src/__tests__/index.spec.ts

@@ -86,7 +86,7 @@ describe('createChat()', () => {
 				expect.objectContaining({
 					method: 'POST',
 					headers: {},
-					body: expect.stringMatching(/"action":"loadPreviousSession"/),
+					body: expect.stringContaining('"action":"loadPreviousSession"') as unknown,
 					mode: 'cors',
 					cache: 'no-cache',
 				}),
@@ -160,7 +160,7 @@ describe('createChat()', () => {
 					expect.objectContaining({
 						method: 'POST',
 						headers: {},
-						body: expect.stringMatching(/"action":"sendMessage"/),
+						body: expect.stringMatching(/"action":"sendMessage"/) as unknown,
 						mode: 'cors',
 						cache: 'no-cache',
 					}),