feat(duolingo/premium): Refactor EnablePremiumPatch field handling

- Import MethodUtil for improved method handling.
- Update field removal logic to use a more explicit approach.
- Ensure proper targeting of user properties in the LoggedIn constructor.

This refactor enhances code clarity and maintainability by explicitly iterating over fields and improving method reference handling.

Author: Viole403

patches/src/main/kotlin/app/revanced/patches/duolingo/premium/EnablePremiumPatch.kt

@@ -10,6 +10,7 @@ import com.android.tools.smali.dexlib2.AccessFlags
 import com.android.tools.smali.dexlib2.Opcode
 import com.android.tools.smali.dexlib2.iface.instruction.ReferenceInstruction
 import com.android.tools.smali.dexlib2.iface.reference.FieldReference
+import com.android.tools.smali.dexlib2.util.MethodUtil
 
 @Suppress("unused")
 val enablePremiumPatch = bytecodePatch(
@@ -31,12 +32,14 @@ val enablePremiumPatch = bytecodePatch(
 
         // Remove final keyword on fields we want to patch
         val fields = setOf(hasPlusField, subscriberLevelField, isPaidField)
-        fields.forEach { userFingerprint.classDef.fieldByName(it.name).removeFlag(AccessFlags.FINAL) }
+        fields.forEach { field ->
+            userFingerprint.classDef.fields.first { it.name == field.name }.removeFlags(AccessFlags.FINAL)
+        }
 
         // For patching user properties, we target the User object that is passed in to the
         // constructor of the LoggedIn class. This way we don't affect all instances of users
         // (eg. viewing a friend's profile).
-        loggedInStateFingerprint.classDef.constructor().apply {
+        loggedInStateFingerprint.classDef.methods.first { MethodUtil.isConstructor(it) }.apply {
             val userType = userFingerprint.classDef.type
             val patchIndex = this.instructions.count() - 1
             // Single-parameter method means User will always be in p1.