chore: we don't need to check if the url is valid in upsert screen.

androidApp/src/main/res/values/strings.xml

@@ -23,7 +23,6 @@
     <string name="all_posts_not_read">"All posts weren't read"</string>
     <string name="all_posts_read">"All posts were read"</string>
     <string name="undo_string">"Undo"</string>
-    <string name="addStringNoUrl">"Log in to add sources."</string>
     <string name="cant_get_sources">"Can't get sources list."</string>
     <string name="cant_create_source">"Can't create source."</string>
     <string name="cant_get_spouts_no_network">"Can't get spouts list because of a network issue."</string>
@@ -109,7 +108,6 @@
     <string name="open_sans_font_id" translatable="false">open_sans</string>
     <string name="roboto_font_id" translatable="false">roboto</string>
     <string name="remove_source">Remove source</string>
-    <string name="pref_theme_title">Light/Dark mode</string>
     <string name="mode_dark">Dark mode</string>
     <string name="mode_system">Follow the system setting</string>
     <string name="mode_light">Light mode</string>