SHARE-518 Enhance Email validation

[EifonUser]

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Your checklist for this pull request

Please review the contributing guidelines and wiki pages of this repository.

• Include the name and id of the Jira ticket in the PR’s title eg.: SHARE-666 The devils ticket
• Choose the proper base branch (develop)
• Confirm that the changes follow the project’s coding guidelines
• Verify that the changes generate no warnings and errors
• Verify to commit no other files than the intentionally changed ones
• Include reasonable and readable tests verifying the added or changed behavior
• Verify that all tests are passing (CI), if not please state the test cases in the section below
• Perform a self-review of the changes
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• Verify that your changes do not have any conflicts with the base branch
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Additional Description

TODO: Add additional information that is not in your commit-message here

Tests - additional information

TODO: add additional information about testruns here

[codecov]

Codecov Report

Merging #3908 (794f453) into develop (3a863d1) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@              Coverage Diff              @@
##             develop    #3908      +/-   ##
=============================================
+ Coverage      49.99%   50.03%   +0.04%     
- Complexity      5705     5713       +8     
=============================================
  Files            654      654              
  Lines          20448    20467      +19     
=============================================
+ Hits           10222    10241      +19     
  Misses         10226    10226              

Flag	Coverage Δ
behat	47.87% <100.00%> (+0.04%)	⬆️
phpunit	8.71% <0.00%> (-0.01%)	⬇️

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Impacted Files	Coverage Δ
src/Api/Services/User/UserRequestValidator.php	75.96% <100.00%> (+5.37%)	⬆️

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