mls (v4.3) (#1578)

## Description:

mls for v24
Version identifier within MLS: v4.3

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I have read and accepted the CLA aggreement (only required once).

## Please put your Discord username so you can be contacted if a bug or
regression is found:

Aotumuri

src/client/LangSelector.ts

@@ -24,6 +24,7 @@ import pl from "../../resources/lang/pl.json";
 import pt_BR from "../../resources/lang/pt-BR.json";
 import ru from "../../resources/lang/ru.json";
 import sh from "../../resources/lang/sh.json";
+import sl from "../../resources/lang/sl.json";
 import sv_SE from "../../resources/lang/sv-SE.json";
 import tp from "../../resources/lang/tp.json";
 import tr from "../../resources/lang/tr.json";
@@ -69,6 +70,7 @@ export class LangSelector extends LitElement {
     "zh-CN": zh_CN,
     ko,
     gl,
+    sl,
   };
 
   createRenderRoot() {