[MC-267071] The word "packs" within the "download.pack.failed" string is always pluralized

The Bug:

The word "packs" within the "download.pack.failed" string is always pluralized.

This is an issue because when the value before the given noun is "1", the noun's plural form is used instead of its singular one, therefore making the string grammatically incorrect in some cases.

Affected Strings:

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
download.pack.failed	%s out of %s packs failed to download	%s out of %s pack(s) failed to download	https://crowdin.com/translate/minecraft/10038/enus-engb#5365118

Alternatively, instead of having one string cover both the plural and non-plural variants of the word, two separate translation strings could be created, one of which covers the plural variant and the other that covers the non-plural variant.

Steps to Reproduce:

Display the affected string as listed above by using the command provided below.
```
/tellraw @s {"translate":"download.pack.failed"}
```
Look closely at the affected word within the string.

Observed Behavior:

The word "packs" is always pluralized.

Expected Behavior:

The word "packs" would be correctly singularized or pluralized where appropriate.