Fix #5410: fix issue with missing update on CMS metadata and end user agreement

[FrancescoMolinaro]

References

Fixes: #5410

Description

Adapted find method of site data service to use projections and so include all languages.

Instructions for Reviewers

Improved method in data service, improved tests.

Steps to reproduce the behavior:

Go to Edit user agreement.
Add a user agreement in any language. Example: Italian.
Create a new account.
Click the activation link from the email inbox.
Change the language.
Observe that the copy does change.

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