refactor: remove unused code from ProjectRepresentativeDialog

- Remove conflictChecker prop (always passed as no-op function)
- Remove unused emitCancel method and cancel event handling
- Simplify handleEntitySelected by removing unnecessary type check
- Update NewEditProjectView to remove conflict-checker binding and empty cancel handler

The conflictChecker prop was not needed since representative selection
doesn't require conflict detection. The cancel event was never emitted
and the parent handler was empty, so both were removed.

src/views/NewEditProjectView.vue

@@ -110,10 +110,8 @@
       :all-contacts="allContacts"
       :active-did="activeDid"
       :all-my-dids="allMyDids"
-      :conflict-checker="() => false"
       :notify="$notify"
       @assign="handleRepresentativeAssigned"
-      @cancel="handleRepresentativeCancel"
     />
 
     <div class="mb-4">
@@ -1062,13 +1060,6 @@ export default class NewEditProjectView extends Vue {
     this.agentDid = contact.did;
   }
 
-  /**
-   * Handle representative dialog cancel
-   */
-  handleRepresentativeCancel(): void {
-    // Dialog closes itself, nothing to do here
-  }
-
   /**
    * Unset the representative and revert to initial state
    */