[core] fix wrong order of message status flags in conversation headers

...rg/briarproject/briar/api/blog/BlogInvitationRequest.java

...g/briarproject/briar/api/blog/BlogInvitationResponse.java

...arproject/briar/api/conversation/ConversationRequest.java

...rproject/briar/api/conversation/ConversationResponse.java

.../briarproject/briar/api/forum/ForumInvitationRequest.java

...briarproject/briar/api/forum/ForumInvitationResponse.java

...arproject/briar/api/introduction/IntroductionRequest.java

...rproject/briar/api/introduction/IntroductionResponse.java

...r/api/privategroup/invitation/GroupInvitationRequest.java

.../api/privategroup/invitation/GroupInvitationResponse.java

...org/briarproject/briar/api/sharing/InvitationRequest.java

...rg/briarproject/briar/api/sharing/InvitationResponse.java

...arproject/briar/introduction/IntroductionManagerImpl.java

...r/privategroup/invitation/GroupInvitationManagerImpl.java

.../briar/privategroup/invitation/InviteeProtocolEngine.java

...briarproject/briar/sharing/BlogInvitationFactoryImpl.java

...riarproject/briar/sharing/ForumInvitationFactoryImpl.java

...oject/briar/introduction/IntroductionIntegrationTest.java

...ivategroup/invitation/GroupInvitationIntegrationTest.java

...riarproject/briar/sharing/BlogSharingIntegrationTest.java