Properly catch password policy hint for personal page password changes

[MorrisJobke]

• before: changing password to abc with password policy app enabled causes 503 and the password change text stays forever with no user feedback
• with this: the proper hint message is shown

@karlitschek I would like to backport this to stable9 and stable10

cc @LukasReschke @nickvergessen @rullzer @schiessle @ChristophWurst

[mention-bot]

@MorrisJobke, thanks for your PR! By analyzing the history of the files in this pull request, we identified @rullzer to be a potential reviewer.

[MorrisJobke]

Review this: https://github.com/nextcloud/server/pull/1634/files?w=1

[karlitschek]

please backport 👍

[LukasReschke]

https://github.com/nextcloud/server/blob/c0660331ea75a177524c452b2c5554080e4231e2/tests/Core/Controller/ChangePasswordControllerTest.php ? 🙈

[MorrisJobke]

https://github.com/nextcloud/server/blob/c0660331ea75a177524c452b2c5554080e4231e2/tests/Core/Controller/ChangePasswordControllerTest.php ?

Test added ;)

[nickvergessen]

Works 👍

[raghunayyar]

Awesome. 👍

[codecov-io]

Current coverage is 55.94% (diff: 31.57%)

Merging #1634 into master will increase coverage by <.01%

@@             master      #1634   diff @@
==========================================
  Files          1070       1070          
  Lines         60817      60859    +42   
  Methods        6838       6841     +3   
  Messages          0          0          
  Branches          0          0          
==========================================
+ Hits          34022      34049    +27   
- Misses        26795      26810    +15   
  Partials          0          0          

Diff Coverage	File Path
••• 31%	settings/Controller/ChangePasswordController.php

Powered by Codecov. Last update ea9b1cc...c84dc6a

[MorrisJobke]

Tested with stable9 and stable10 and there it works fine. This was a regression due to #868