feat(amazonq): env var change for JupyterLab conversation history on refresh support

use SAGEMAKER_APP_TYPE_LOWERCASE env var

**Description**

**Testing Done**

Author: ruotingx

server/aws-lsp-codewhisperer/src/language-server/agenticChat/tabBarController.test.ts

@@ -50,7 +50,7 @@ describe('TabBarController', () => {
     afterEach(() => {
         sinon.restore()
         clock.restore()
-        delete process.env.JUPYTER_LAB // Clean up JupyterLab environment variables
+        delete process.env.SAGEMAKER_APP_TYPE_LOWERCASE // Clean up JupyterLab environment variables
         testFeatures.dispose()
     })
 
@@ -563,7 +563,7 @@ describe('TabBarController', () => {
 
         it('should allow multiple loads in JupyterLab environment', async () => {
             // Set JupyterLab environment
-            process.env.JUPYTER_LAB = 'true'
+            process.env.SAGEMAKER_APP_TYPE_LOWERCASE = 'jupyterlab'
 
             const mockTabs = [{ historyId: 'history1', conversations: [{ messages: [] }] }] as unknown as Tab[]
             ;(chatHistoryDb.getOpenTabs as sinon.SinonStub).returns(mockTabs)

server/aws-lsp-codewhisperer/src/language-server/agenticChat/tabBarController.ts

@@ -344,9 +344,9 @@ export class TabBarController {
      */
     private isJupyterLabEnvironment(): boolean {
         try {
-            return process.env.JUPYTER_LAB === 'true'
+            return process.env.SAGEMAKER_APP_TYPE_LOWERCASE === 'jupyterlab'
         } catch (error) {
-            this.#features.logging.error(`Failed to read JUPYTER_LAB environment variable: ${error}`)
+            this.#features.logging.error(`Failed to read SAGEMAKER_APP_TYPE_LOWERCASE environment variable: ${error}`)
             return false
         }
     }