fix(csv): assign result of replace in splitCSV else branch

The replace() call in the unquoted-field path was discarding its return
value, leaving "" sequences unescaped instead of collapsing them to ".

ui-ngx/src/app/shared/import-export/import-export.models.ts

@@ -210,7 +210,7 @@ function splitCSV(str: string, sep: string): string[] {
         foo = foo.shift().split(sep).concat(foo);
       }
     } else {
-      foo[x].replace(/""/g, '"');
+      foo[x] = foo[x].replace(/""/g, '"');
     }
   }
   return foo;