build: update OkHttp 5.0.0-alpha.3 to 5.3.0 stable

Move off the pre-release alpha to the current stable OkHttp 5.x line.
5.3.0 is the latest stable whose okhttp-android artifact still supports
compileSdk 35 (5.4.0 requires minCompileSdk=36). The network-client API used
(OkHttpClient, newCall/execute, Request.Builder, Credentials.basic,
toMediaType/toRequestBody, HttpUrl) is stable across 5.x; no source changes.

Author: hawkff

app/build.gradle.kts

@@ -65,7 +65,7 @@ dependencies {
     implementation("com.blacksquircle.ui:language-base:2.6.0")
     implementation("com.blacksquircle.ui:language-json:2.6.0")
 
-    implementation("com.squareup.okhttp3:okhttp:5.0.0-alpha.3")
+    implementation("com.squareup.okhttp3:okhttp:5.3.0")
     implementation("org.yaml:snakeyaml:2.3")
     implementation("com.github.daniel-stoneuk:material-about-library:3.2.0-rc01")
     implementation("com.jakewharton:process-phoenix:2.1.2")