cli command "task <filter> duplicate" does not duplicate all attributes of task

#### To report a bug...

* What command(s) did you run?
``task 1 duplicate``
* What did you expect to happen?
Task with ID 1 should have been fully duplicated.
Task with ID 1 has assigned values for the ``until`` and ``recur`` attributes.
New duplicated task with ID 2 should also have the same value as the task with ID 1 for the ``due`` and ``recur`` attributes.
* What actually happened?
New duplicated task with ID 2 does not have values for either the ``until`` or ``recur`` attributes.
* Paste the output of the ```task diag``` command.
```
task 2.6.2
Platform: Linux

Compiler
Version: 11.2.0
Caps: +stdc +stdc_hosted +LP64 +c8 +i32 +l64 +vp64 +time_t64
Compliance: C++17

Build Features
CMake: 3.22.3
libuuid: libuuid + uuid_unparse_lower
libgnutls: 3.7.3
Build type:

Configuration
File: /home/starlight/.taskrc (found), 1384 bytes, mode 100644
Data: /home/starlight/.task (found), dir, mode 40755
Locking: Enabled
GC: Enabled
Server:
CA: -
Certificate: -
Key: -
Trust: strict
Ciphers: NORMAL
Creds:

Hooks
System: Enabled
Location: /home/starlight/.task/hooks
(-none-)

Tests
Terminal: 210x103
Dups: Scanned 16 tasks for duplicate UUIDs:
No duplicates found
Broken ref: Scanned 16 tasks for broken references:
No broken references found
```