[Backport] Fix for #12399: Exception Error in Catalog Price Rule while Backend language is not English

[Mardl]

Original Pull Request
#18419

Fix for: #12399 cause it's not fixed in 2.2-develop

Description

I took the fix from #12399 (comment) cause it's almost identical code like
app/code/Magento/SalesRule/Controller/Adminhtml/Promo/Quote/Save.php:30

Fixed Issues (if relevant)

1. Exception Error in Catalog Price Rule while Backend language is not English #12399 : Exception Error in Catalog Price Rule while Backend language is not English

Manual testing scenarios

https://youtu.be/xBMxMfKHmuc

1. Go to: System -> All User -> [Choose your user]
2. Change Interface Locale to Italien or French or Portuguese
3. Relogin with this user
4. Go to: Marketing -> catalog price rule
5. Edit a record already created (or create a new)
6. Set date From and/or To for example 20 Mai 2019 (Portuguese like "20/02/2019")
7. Click on "Save and Apply"

PHP DateTime can not work with that format. Same problem in Promo/Quote/Save was fixed 2014 and 2016. Maybe forget to fix in Promo/Catalog/Save too.

Contribution checklist

• [X ] Pull request has a meaningful description of its purpose
• [X ] All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

Hi @Mardl. Thank you for your contribution
Here is some useful tips how you can test your changes using Magento test environment.
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[magento-engcom-team]

Hi @josefbehr, thank you for the review.
ENGCOM-3396 has been created to process this Pull Request

[magento-engcom-team]

Hi @Mardl. Thank you for your contribution.
We will aim to release these changes as part of 2.2.8.
Please check the release notes for final confirmation.

Please, consider to port this solution to 2.3 release line.
You may use Porting tool to port commits automatically.

[Mardl]

@magento-engcom-team this was just a backport from #18419 . It is already in 2.3-develop and will be in 2.3.1 release