IBX-3265: Fixed translation of User content objects

[webhdx]

JIRA: https://issues.ibexa.co/browse/IBX-3265
Requires: ezsystems/ezplatform-admin-ui#2081

Looks like translating User content objects was never working properly. Architecture of Content editing forms is very limiting thus the solution is not perfect. It required a few steps to fix the issue:

• User object with incorrect language was passed to UserUpdateMapper which prevented displaying an editing form
• FieldValueValidator was defined as data constraint which had to be changed to form constraint in order to provide more context to the validator. Intuitively you'd use validation groups here but it isn't possible with how we dynamically map fields. Right now the form will define FieldValue constraint with intent option passed as payload. Then the validator itself can detect wether it should skip validation on nontranslatable fieldtypes.
• Translation has to use it's own intent. Previously we heavily relied on translations being content updates but it was very limiting in places where you can't access Content object to check mainLanguageCode.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
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No Coverage information
0.0% Duplication

[bogusez]

Regression tests passed: ibexa/commerce#168