Fix crash when Shortcut labels are empty

[jmartinesp]

Content

What the title says. If a room name is empty and we try to use that room name as a label for a shortcut, it will throw an exception that's not caught.

Motivation and context

Fix a crash:

Exception java.lang.IllegalArgumentException: Shortcut must have a non-empty label
  at androidx.core.content.pm.ShortcutInfoCompat$Builder.build (ShortcutInfoCompat.java:919)
  at io.element.android.libraries.push.impl.notifications.conversations.DefaultNotificationConversationService.onSendMessage-L2ILk2A (DefaultNotificationConversationService.kt:119)
  at io.element.android.libraries.push.impl.notifications.conversations.DefaultNotificationConversationService$onSendMessage$1.invokeSuspend (DefaultNotificationConversationService.kt:18)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:34)
  at kotlinx.coroutines.internal.ScopeCoroutine.afterResume (Scopes.kt:35)
  at kotlinx.coroutines.AbstractCoroutine.resumeWith (AbstractCoroutine.kt:101)
  at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith (ContinuationImpl.kt:47)
  at kotlinx.coroutines.DispatchedTask.run (DispatchedTask.kt:100)
  at android.os.Handler.handleCallback (Handler.java:958)
  at android.os.Handler.dispatchMessage (Handler.java:99)
  at android.os.Looper.loopOnce (Looper.java:224)
  at android.os.Looper.loop (Looper.java:318)
  at android.app.ActivityThread.main (ActivityThread.java:8772)
  at java.lang.reflect.Method.invoke
  at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run (RuntimeInit.java:561)
  at com.android.internal.os.ZygoteInit.main (ZygoteInit.java:1013)

Tests

To be honest, I'm not sure how to reproduce it: this needs the room to have no name and not auto-create one from existing users. I thought an empty room where you're the only user present would be enough, but in the debugger I see 'Empty room' being the room display name, so I don't really know how you can get in a state where the room name isn't automatically generated and it's just empty.

Tested devices

• Physical
• Emulator
• OS version(s): 16

Checklist

• Changes have been tested on an Android device or Android emulator with API 24
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• Pull request title will be used in the release note, it clearly define what will change for the user
• Pull request includes screenshots or videos if containing UI changes
• You've made a self review of your PR

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

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[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 81.38%. Comparing base (c5bb18c) to head (bcb4e45).

Files with missing lines	Patch %	Lines
...rsations/DefaultNotificationConversationService.kt	66.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #5895      +/-   ##
===========================================
- Coverage    81.38%   81.38%   -0.01%     
===========================================
  Files         2479     2479              
  Lines        66200    66201       +1     
  Branches      8431     8432       +1     
===========================================
  Hits         53876    53876              
  Misses        9221     9221              
- Partials      3103     3104       +1     

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