refactor: Remove unused imports in MainActivity

This commit cleans up `MainActivity.kt` by removing unused imports related to Jetpack Compose and application navigation.

- `MainActivity.kt`: Removed `setContent`, `AppTheme`, and `ApplicationNavigation` imports.

Author: JoshLudahl

app/src/main/java/com/warbler/MainActivity.kt

@@ -3,7 +3,6 @@ package com.warbler
 import android.os.Bundle
 import android.util.Log
 import android.widget.Toast
-import androidx.activity.compose.setContent
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.appcompat.app.AppCompatActivity
 import androidx.databinding.DataBindingUtil
@@ -19,9 +18,7 @@ import com.google.android.play.core.install.InstallStateUpdatedListener
 import com.google.android.play.core.install.model.AppUpdateType
 import com.google.android.play.core.install.model.InstallStatus
 import com.google.android.play.core.install.model.UpdateAvailability
-import com.warbler.core.theme.AppTheme
 import com.warbler.databinding.ActivityMainBinding
-import com.warbler.navigation.ApplicationNavigation
 import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.launch