Fix youtube restrict test failure due to warning text change

Validation: https://ci.chromium.org/p/chromium/builders/try/win-celab-try-rel/102

Change-Id: I8b797a034515d71ad40be739b6b96199e29563d7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1970910Reviewed-by: Owen Min <zmin@chromium.org>
Commit-Queue: Xiang Ji <jxiang@google.com>
Cr-Commit-Position: refs/heads/master@{#726453}

chrome/test/enterprise/e2e/policy/youtube_restrict/youtube_restrict.py

@@ -14,8 +14,7 @@ class YouTubeRestrictTest(ChromeEnterpriseTestCase):
 
   See https://cloud.google.com/docs/chrome-enterprise/policies/?policy=ForceYouTubeRestrict"""
 
-  RestrictedText = "This video is restricted. " \
-      + "Try signing in with a Google Apps account."
+  RestrictedText = "This video is restricted. "
 
   @before_all
   def setup(self):