message: use contact api to determine omemo encryption state
diff: @@ -36,11 +36,7 @@ export default class OMEMOPlugin extends EncryptionPlugin {
  return;
  }
  - let storage = this.pluginAPI.getStorage();
  - let enabled = !storage.getItem('enabled', contact.getJid().bare);
  - storage.setItem('enabled', contact.getJid().bare, enabled);
  -
  - if (!enabled) {
  + if (contact.getEncryptionPluginName() === OMEMOPlugin.getName()) {
  contact.setEncryptionState(EncryptionState.Plaintext, OMEMOPlugin.getName());
  return;
  }
  @@ -110,9 +106,7 @@ export default class OMEMOPlugin extends EncryptionPlugin {
  return Promise.resolve([message, xmlElement]);
  }
  - let enabled = !!this.pluginAPI.getStorage().getItem('enabled', contact.getJid().bare);
  -
  - if (!enabled) {
  + if (contact.getEncryptionPluginName() !== OMEMOPlugin.getName()) {
  return Promise.resolve([message, xmlElement]);
  }
  