When saving if the Security Key is not available the prompt for it

[gjwgit]

The solidui package includes a widget to request the security key.

Currently I get:

I/flutter (31073): Exception: You must first set the security key!
I/flutter (31073): #0      KeyManager.getMasterKey (package:solidpod/src/solid/utils/key_manager.dart:185:9)
I/flutter (31073): <asynchronous suspension>
I/flutter (31073): #1      KeyManager.getIndividualKey (package:solidpod/src/solid/utils/key_manager.dart:427:7)
I/flutter (31073): <asynchronous suspension>
I/flutter (31073): #2      retrieveEncKey (package:solidpod/src/solid/utils/key_inheritance.dart:104:15)
I/flutter (31073): <asynchronous suspension>
I/flutter (31073): #3      readPod (package:solidpod/src/solid/read_pod.dart:133:20)
I/flutter (31073): <asynchronous suspension>
I/flutter (31073): #4      _HistoryState._loadSessions (package:innerpod/widgets/history.dart:44:19)
I/flutter (31073): <asynchronous suspension>
I/flutter (31073): 
I/flutter (31073): sessions.ttl does not exist yet: Exception: You must first set the security key!

The message is incorrect. The session.ttl file does exist.