Fix AVAudioSession activation in push notification context on iOS (#174)

[evdokimovs]

Resolves #174

Synopsis

Read #174 issue.

Solution

Use try? instead of try! in AVAudioSession activation.

Checklist

• Created PR:
  • In draft mode
  • Name contains issue reference
  • Has type and k:: labels applied
  • Has assignee
• Before review:
  • Documentation is updated (if required)
  • Tests are updated (if required)
  • Changes conform code style
  • CHANGELOG entry is added (if required)
  • FCM (final commit message) is posted or updated
  • Draft mode is removed
• Review is completed and changes are approved
  • FCM (final commit message) is approved
• Before merge:
  • Milestone is set
  • PR's name and description are correct and up-to-date
  • All temporary labels are removed

[evdokimovs]

FCM

Fix `AVAudioSession` activation in push notification context on iOS (#175, #174)