[Password manager tests automation] Wait longer for SAVE/ASK

When the tests determine, whether Chrome displayed a "save password" prompt appropriately (or saved automatically in the setting skipping the UI), it scrapes the password internals page for the corresponding ASK/SAVE message.

There is a delay between a new page loads and this message appears. Currently the tests wait max. 3 seconds until giving up. That breaks often.

This CL changes that to 15 seconds, curing some of the tests. Note that if the message is received earlier, the tests don't wait for the rest of the timeout, so this should not make the test duration unnecessarily longer.

BUG=369521
R=battre@chromium.org

Review URL: https://codereview.chromium.org/1009573003

Cr-Commit-Position: refs/heads/master@{#320708}

components/test/data/password_manager/automated_tests/environment.py

@@ -276,7 +276,7 @@ class Environment:
       return False
 
   def CheckForNewMessage(self, log_message, message_should_show_up,
-                         error_message, timeout=3):
+                         error_message, timeout=15):
     """Detects whether the save password prompt is shown.
 
     Args: