iOS can't recieve Telegram calls in Do not disturb when it's always active

Checklist

• I am reporting an issue in existing functionality that does not work as intended
• I've searched for existing GitHub issues

Description

If you turn on the option to not get any calls (even the second call) and the option to keep the Do not disturb mode while iPhone is active, then while taking a Telegram call you will not be able to answer it (even from Favorite contacts who are allowed to iPhone-call you). It's just a green bar appears on the top of the screen, saying "Touch to get back to the call" (or smth like that), but when you touch it, the screen freezes for 1-2 seconds and nothing is happening until you switch off the Do not disturb mode. Videocalls have the same problem [Telegram 7.0, iOS 13.3.1]

Expected Behavior

Calls wouldn't appear on the screen, and the one who calls get a notification or at least the call is recieved correctly.

Actual Behavior

The green bar "Touch to get back to the call" is shown on the top, when you touch it, the screen freezes for 1-2 seconds.

Steps to Reproduce

1. Turn on "Do not disturb" mode on iOS
2. Make silent mode forever, not only when iPhone is locked, maybe also make a second call disabled, so no one can call you except favs
3. Try to get a call from anyone (even from favs) while Telegram is open

Screenshots and Videos

Environment

Device: iPhone 7

iOS version: 13.3.1

App version: 7.0 (17743)

Reproduce on an iPhone 7 with iOS 13.3.1 and Telegram 7.0 (17743), using Do Not Disturb, persistent silence, and a Telegram call while the app is open. Done means incoming voice and video calls behave correctly under these settings without the green-bar freeze.