Revert "Use err.errorNum instead of err.code"

This reverts commit d90713b.

Author: pluma

src/collection.ts

@@ -3584,7 +3584,7 @@ export class Collection<T extends Record<string, any> = any>
         () => true
       );
     } catch (err) {
-      if (isArangoError(err) && err.errorNum === DOCUMENT_NOT_FOUND) {
+      if (err.code === 404) {
         return false;
       }
       throw err;

src/graph.ts

@@ -489,7 +489,7 @@ export class GraphVertexCollection<T extends Record<string, any> = any>
         () => true
       );
     } catch (err) {
-      if (isArangoError(err) && err.errorNum === DOCUMENT_NOT_FOUND) {
+      if (err.code === 404) {
         return false;
       }
       throw err;
@@ -894,7 +894,7 @@ export class GraphEdgeCollection<T extends Record<string, any> = any>
         () => true
       );
     } catch (err) {
-      if (isArangoError(err) && err.errorNum === DOCUMENT_NOT_FOUND) {
+      if (err.code === 404) {
         return false;
       }
       throw err;