fix(polling): remove unused variable and preserve lastModifiedTime on Drive API failure

- Remove unused `now` variable from Google Drive polling handler
- Preserve stored lastModifiedTime when Drive API pre-check fails
  (previously wrote undefined, disabling the optimization until the
  next successful Drive API call)

apps/sim/lib/webhooks/polling/google-drive.ts

@@ -87,7 +87,6 @@ export const googleDrivePollingHandler: PollingProviderHandler = {
       )
 
       const config = webhookData.providerConfig as unknown as GoogleDriveWebhookConfig
-      const now = new Date()
 
       // First poll: get startPageToken and seed state
       if (!config.pageToken) {

apps/sim/lib/webhooks/polling/google-sheets.ts

@@ -95,7 +95,7 @@ export const googleSheetsPollingHandler: PollingProviderHandler = {
           webhookId,
           {
             lastKnownRowCount: currentRowCount,
-            lastModifiedTime: currentModifiedTime,
+            lastModifiedTime: currentModifiedTime ?? config.lastModifiedTime,
             lastCheckedTimestamp: now.toISOString(),
           },
           logger
@@ -118,7 +118,7 @@ export const googleSheetsPollingHandler: PollingProviderHandler = {
           webhookId,
           {
             lastKnownRowCount: currentRowCount,
-            lastModifiedTime: currentModifiedTime,
+            lastModifiedTime: currentModifiedTime ?? config.lastModifiedTime,
             lastCheckedTimestamp: now.toISOString(),
           },
           logger
@@ -195,7 +195,9 @@ export const googleSheetsPollingHandler: PollingProviderHandler = {
         webhookId,
         {
           lastKnownRowCount: newLastKnownRowCount,
-          lastModifiedTime: hasRemainingOrFailed ? config.lastModifiedTime : currentModifiedTime,
+          lastModifiedTime: hasRemainingOrFailed
+            ? config.lastModifiedTime
+            : (currentModifiedTime ?? config.lastModifiedTime),
           lastCheckedTimestamp: now.toISOString(),
         },
         logger