fix(l10n): Update Bulgarian translations

Currently translated at 50.0% (14 of 28 strings)

Translation: Pachli/Core/Preferences : Main
Translate-URL: https://hosted.weblate.org/projects/pachli/corepreferences-main/bg/

core/preferences/src/main/res/values-bg/strings.xml

@@ -12,4 +12,6 @@
     <string name="pref_main_nav_position_option_bottom">Долу</string>
     <string name="pref_show_self_username_always">Винаги</string>
     <string name="pref_show_self_username_never">Никога</string>
+    <string name="pref_tab_contents_icon_only">Само икона</string>
+    <string name="pref_tab_contents_text_only">Само текст</string>
 </resources>