Bug report: ROT13 of numbers not commutative

**Describe the bug**
ROT13 of numbers is not commutative/symetric. Applying an identical ROT13 operator with "Rotate numbers" enabled twice to an input with numbers in it won't result in the original input.

**To Reproduce**
[Link to recipe](https://gchq.github.io/CyberChef/#recipe=ROT13(false,false,true,13)ROT13(false,false,true,7)&input=MDEyMzQ1Njc4OQ)

**Expected behaviour**
Expecto be able to decipher a string ciphered with a ROT13 operator with a ROT13 operator with identical settings.

**Screenshots**

**Desktop (if relevant, please complete the following information):**
- OS: Windows 10
- Browser: Chrome/110.0.0.0
- CyberChef version: 9.55.0 (09/12/2022 11:42:13 UTC)

Start with the linked CyberChef recipe and the ROT13 operation, reproducing the behavior with numbers enabled and comparing repeated applications. The work is done when applying the same ROT13 settings twice restores the original numeric input, with a regression test covering the reported case.

Written by the indexing model from the issue text.