refactor(annotations): replace global element index with element.id in generateId

- Removed global __elementIndex counter and updated generateId() to use element.id for unique annotation IDs.
- Updated createAnnotations() and createImageAnnotation() to pass element.id to generateId().
- Simplified ID generation logic for better consistency and traceability across annotations.

EnvelopeGenerator.Web/wwwroot/js/app.js

@@ -90,6 +90,7 @@ class App {
                 imageAttachmentId,
                 this.envelopeReceiver.envelopeId,
                 this.envelopeReceiver.receiverId,
+                this.fakeElementId--,
                 'signature'
             )
 
@@ -281,11 +282,7 @@ class App {
             .map(a => a.toJS())
             .filter(a => a.isSignature)
 
-        if (totalSignatures > filtered.length) {
-            return false
-        } else {
-            return true
-        }
+        return totalSignatures <= filtered.length
     }
 
     async handleReset(event) {
@@ -302,4 +299,6 @@ class App {
 
         return result
     }
+
+    fakeElementId = 0;
 }