Editor: Fix Path Traversal issue on Windows in Template-Part Block. #12907

Job	Run time
Test npm on ubuntu-latest	51s
Test npm on ubuntu-latest	51s
Test npm on windows-latest	1m 45s
Test npm on windows-latest	1m 45s
Test npm on MacOS	7s
Test npm on MacOS	8s
Slack Notifications / Prepare notifications	2s
Slack Notifications / Prepare notifications	4s
Slack Notifications / Cancelled notifications	0s
Slack Notifications / Cancelled notifications	0s
Slack Notifications / Failure notifications	0s
Slack Notifications / Failure notifications	3s
Slack Notifications / Fixed notifications	0s
Slack Notifications / Fixed notifications	0s
Slack Notifications / Success notifications	0s
Slack Notifications / Success notifications	0s
Failed workflow tasks	2s
Failed workflow tasks	0s
	5m 38s

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