Fix new extension install not registering in app. (#275)

* Fix extension install not registering

* fix duplicate key compose error on extension update

* fix doubling of extension after update

* not needed

(cherry picked from commit 79f46b25f663c7f49fbd4e292f0f5f210e266dc9)

app/src/main/java/eu/kanade/tachiyomi/extension/ExtensionManager.kt

@@ -406,9 +406,12 @@ class ExtensionManager(
         override fun onExtensionUntrusted(extension: Extension.Untrusted) {
             val installedExtension = _installedExtensionsFlow.value
                 .find { it.pkgName == extension.pkgName }
-                ?: return
-            _installedExtensionsFlow.value -= installedExtension
-            _untrustedExtensionsFlow.value += extension
+
+            if (installedExtension != null) {
+                _installedExtensionsFlow.value -= installedExtension
+            } else {
+                _untrustedExtensionsFlow.value += extension
+            }
         }
 
         override fun onPackageUninstalled(pkgName: String) {