Fix failed tests on action planpreview (#6256)

Signed-off-by: khanhtc1202 <khanhtc1202@gmail.com>
Signed-off-by: pipecd-bot <pipecd.dev@gmail.com>

Author: khanhtc1202

tool/actions-plan-preview/testdata/comment-plugin-has-failed-app.txt

@@ -10,6 +10,7 @@ Sync strategy: PIPELINE
   Plugin(s): kubernetes
   Summary:
   - kubernetes(dt-1): 2 resources will be added, 1 resource will be deleted and 5 resources will be changed
+
   Details:
   - kubernetes(dt-1):
 <details>

tool/actions-plan-preview/testdata/comment-plugin-one-success-app.txt

@@ -10,6 +10,7 @@ Sync strategy: QUICK_SYNC
   Plugin(s): kubernetes
   Summary:
   - kubernetes(dt-1): 2 resources will be added, 1 resource will be deleted and 5 resources will be changed
+
   Details:
   - kubernetes(dt-1):
 <details>