Unable to recieve incomming calls

#### Describe the bug.
When someone calls to me I see the silent notification but if the app is closed there is no native call screen shown and because of that I can't attend the call

#### Steps to reproduce:
Steps to reproduce the behaviour:

- iOS device has Element iOS 1.4.7 installed and has logged into an account.
- Have another account initiate a one-to-one voice call with the first account
- Notice incoming notifications (silent?) but no incoming call screen.

#### Expected behaviour
Element app used to make the device ring by way of native call screen when the app is closed.

- Device: iPhone 6
- OS: ios 12.5.4
- App Version: 1.4.7