[Backport] FIX for issue#14869 - Wrong price at backend after update

[sergiy-v]

Original PR: #14904.

A previous commit 9d3be73 (cc @neeta-wagento) changed the default behaviour of
\Magento\Quote\Model\ResourceModel\Quote\Item\Collection::getStoreId() using the store coming from the current session
instead of using the one from quote. The previous commit was made to fix an error while using getItems() without setting a quote.
The implemetation is correctly working in the frontend because the quote storeId is and the session storeId are matchnig, but it breaks the admin implementation because they can be different.

The current fix restore the previous behaviour and adds a check if the quote is not specified.

Fixed Issues (if relevant)

1. M 2.2.3 price per website - wrong price at backend by a create order after update #14869: Wrong price at backend after update

Contribution checklist

• Pull request has a meaningful description of its purpose
• 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)

[VladimirZaets]

Hi @sergiy-v. As I see, the commit 9d3be is absent in the 2.1 branch, so this fix is no relevant.

Can you please make backport changes from the commit 9d3be too. Thanks

[VladimirZaets]

@sergiy-v, I am closing this PR now due to inactivity.
Please reopen and update if you wish to continue.
Thank you for collaboration