Ensure LevelDB Iterator is closed (#5458)

Task/Issue URL:
https://app.asana.com/0/1200204095367872/1209128100809324/f

### Description

- Closes the `DBIterator` after local storage has been cleared.
- Also keeps the DB open and updates the DB initialization to be `Lazy`.

### Steps to test this PR

_Filter logcat by WebLocalStorageManager_
- [x] Visit cnn.com
- [x] Use the fire button
- [x] Verify that cnn.com entries are deleted

app/src/main/java/com/duckduckgo/app/browser/weblocalstorage/WebLocalStorageManager.kt

@@ -21,13 +21,13 @@ import com.duckduckgo.app.pixels.remoteconfig.AndroidBrowserConfigFeature
 import com.duckduckgo.di.scopes.AppScope
 import com.squareup.anvil.annotations.ContributesBinding
 import com.squareup.anvil.annotations.ContributesTo
+import dagger.Lazy
 import dagger.Module
 import dagger.Provides
 import dagger.SingleInstanceIn
 import java.io.File
 import java.nio.charset.StandardCharsets
 import javax.inject.Inject
-import javax.inject.Provider
 import kotlinx.coroutines.runBlocking
 import org.iq80.leveldb.DB
 import org.iq80.leveldb.Options
@@ -40,7 +40,7 @@ interface WebLocalStorageManager {
 
 @ContributesBinding(AppScope::class)
 class DuckDuckGoWebLocalStorageManager @Inject constructor(
-    private val databaseProvider: Provider<DB>,
+    private val databaseProvider: Lazy<DB>,
     private val androidBrowserConfigFeature: AndroidBrowserConfigFeature,
     private val webLocalStorageSettingsJsonParser: WebLocalStorageSettingsJsonParser,
 ) : WebLocalStorageManager {
@@ -58,8 +58,8 @@ class DuckDuckGoWebLocalStorageManager @Inject constructor(
         Timber.d("WebLocalStorageManager: Allowed domains: $domains")
         Timber.d("WebLocalStorageManager: Matching regex: $matchingRegex")
 
-        databaseProvider.get().use { db ->
-            val iterator = db.iterator()
+        val db = databaseProvider.get()
+        db.iterator().use { iterator ->
             iterator.seekToFirst()
 
             while (iterator.hasNext()) {

app/src/test/java/com/duckduckgo/app/browser/DuckDuckGoWebLocalStorageManagerTest.kt

@@ -23,7 +23,7 @@ import com.duckduckgo.app.browser.weblocalstorage.WebLocalStorageSettings
 import com.duckduckgo.app.browser.weblocalstorage.WebLocalStorageSettingsJsonParser
 import com.duckduckgo.app.pixels.remoteconfig.AndroidBrowserConfigFeature
 import com.duckduckgo.feature.toggles.api.Toggle
-import javax.inject.Provider
+import dagger.Lazy
 import kotlinx.coroutines.test.runTest
 import org.iq80.leveldb.DB
 import org.iq80.leveldb.DBIterator
@@ -39,7 +39,7 @@ class DuckDuckGoWebLocalStorageManagerTest {
 
     private val mockDB: DB = mock()
     private val mockIterator: DBIterator = mock()
-    private val mockDatabaseProvider: Provider<DB> = mock()
+    private val mockDatabaseProvider: Lazy<DB> = mock()
     private val mockWebLocalStorageSettingsJsonParser: WebLocalStorageSettingsJsonParser = mock()
     private val mockAndroidBrowserConfigFeature: AndroidBrowserConfigFeature = mock()
     private val mockToggle: Toggle = mock()
@@ -152,13 +152,13 @@ class DuckDuckGoWebLocalStorageManagerTest {
     }
 
     @Test
-    fun whenClearWebLocalStorageThenDBIsClosed() {
+    fun whenClearWebLocalStorageThenIteratorIsClosed() {
         whenever(mockDB.iterator()).thenReturn(mockIterator)
         whenever(mockIterator.hasNext()).thenReturn(false)
 
         testee.clearWebLocalStorage()
 
-        verify(mockDB).close()
+        verify(mockIterator).close()
     }
 
     private fun createMockDBEntry(key: ByteArray): MutableMap.MutableEntry<ByteArray, ByteArray> {