Replace Combine Future with async/await if any left

[ivan-ushakov]

close #1058

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Tests (delete all except exactly one):

• Does not need tests (refactor only, docs or internal changes)

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To be filled by reviewers

I have reviewed that this PR... (tick whichever items you personally focused on during this review):

• addresses the issue it closes (if any)
• code is readable and understandable
• is accompanied with tests, or tests are not needed
• is free of vulnerabilities
• is documented clearly and usefully, or doesn't need documentation

[ivan-ushakov]

We still have one import Combine in ComposeViewController.swift because we use it for some UI logic.

[tomholub]

I'm good to merge this, but some tests are unhappy.

[ivan-ushakov]

I'm good to merge this, but some tests are unhappy.

It works fine locally. We already have issue #1164 for this test.