Make setLocale parameter nullable in Locale class

Changed the setLocale parameter in the Locale class to be nullable and updated its usage to safely invoke it. This allows for more flexible instantiation when a setLocale function is not required.

Author: Stefterv

app/src/processing/app/ui/theme/Locale.kt

@@ -21,7 +21,7 @@ import java.util.*
  * val localizedString = locale["someKey"]
  * ```
  */
-class Locale(language: String = "", val setLocale: (java.util.Locale) -> Unit) : Properties() {
+class Locale(language: String = "", val setLocale: ((java.util.Locale) -> Unit)? = null) : Properties() {
     var locale: java.util.Locale = java.util.Locale.getDefault()
 
     init {
@@ -46,7 +46,7 @@ class Locale(language: String = "", val setLocale: (java.util.Locale) -> Unit) :
     }
     operator fun get(key: String): String = getProperty(key, key)
     fun set(locale: java.util.Locale) {
-        setLocale(locale)
+        setLocale?.invoke(locale)
     }
 }
 /**
@@ -104,7 +104,7 @@ fun LocaleProvider(content: @Composable () -> Unit) {
     val update = watchFile(languageFile)
     var code by remember(languageFile, update){ mutableStateOf(languageFile.readText().substring(0, 2)) }
     remember(code) {
-        val locale = Locale(code)
+        val locale = java.util.Locale(code)
         java.util.Locale.setDefault(locale)
     }