Fixed numeral localization in insulin delivery table view

[hannkm]

Fixes #1968
This fixes the issue of symbols appearing instead of numerals. Changes mainly affect Arabic but all numbers should be displayed correctly according to their language now.

[hannkm]

This is the issue replicated before the change:

This is what it looks now after the fix:

[ps2]

Thanks, can you describe why this is an appropriate change? I don't see it documented that this method expects utf16, and that would be surprising, as usually utf8 is appropriate for these. See this for a possible alternate solution: https://stackoverflow.com/questions/61411944/nsattributedstring-from-utf16-characters-in-uitextview

[ps2]

Hmm, although further searching brings up this page that does seem to indicate that NSAttributedString might be expecting UTF16. https://samwize.com/2016/05/24/nsattributedstring-html-ios-unicode-encoding/

Would be nice if this was documented. Let me know if you have any other references that can shed some light on what is actually expected by the platform.

[hannkm]

Here are some articles I referenced:
https://www.objc.io/issues/9-strings/unicode/ (https://www.objc.io/issues/9-strings/unicode/)
This is the official Apple documents:
https://developer.apple.com/documentation/foundation/nsstring (https://developer.apple.com/documentation/foundation/nsstring)
NSMutableAttributedString requires non-ASCII values to be encoded in UTF-16, and I believe this is the only function (as submitted in this PR) that utilized utf8 encoding for the data entries previously.

Could you clarify where I should document this?