General context isolation issue in the displayers

If asked to, the displayers isolate what they need to executed between DocumentAccessBridge#pushDocumentInContext and DocumentAccessBridge#popDocumentFromContext.

It generally looks like:

try {
  documentAccessBridge.pushDocumentInContext(backupObjects, documentReference);
  execute stuff related to display
} finally {
  documentAccessBridge.popDocumentFromContext(backupObjects);
}

The simple fact that pushDocumentInContext can fail is the issue here: if pushDocumentInContext fail and popDocumentFromContext succeed the current context is lost and pretty much all the following code is broken.

We need to make sure pushDocumentInContext and popDocumentFromContext are always perfectly in sync (make pushDocumentInContext push a context whatever happen or call popDocumentFromContext only if pushDocumentInContext has been fully done or whatever other idea to make sure it's safe).