[MC-279154] The "advancements.story.enter_the_nether.description" string is missing a serial comma

The Bug:

The "advancements.story.enter_the_nether.description" string is missing a serial comma.

For a bit of context, a serial comma is a comma used after the penultimate item in a list of three or more items, typically before the words "and" or "or". For example within the sentence, "We went to the store and bought wheat, carrots, potatoes, and beetroots.", the serial comma is the comma present right after the word "potatoes".

Minecraft's source language, (which is English, United States), commonly makes use of this comma, and since it's present within several other strings throughout the game, this introduces an inconsistency.

Affected String:

Before reading the table, please note the following:

Words colored in GREEN are correct.
Words colored in RED are incorrect.

Translation Key	Current String	Expected String	String URL on Crowdin
advancements.story.enter_the_nether.description	Build, light and enter a Nether Portal	Build, light, and enter a Nether Portal	https://crowdin.com/editor/minecraft/10038/enus-engb?view=comfortable#5340786

Steps to Reproduce:

Display the affected string as listed above by using the command provided below.
```
/tellraw @s {"translate":"advancements.story.enter_the_nether.description"}
```
Observe if the string utilizes a serial comma.

Observed Behavior:

A serial comma is missing.

Expected Behavior:

A serial comma would be present.