v2.6.1

Changed

• update cover image in README.md
• remove settings from about_page.dart to avoid errors when user not logged in yet
• display only local accounts on instance directory page
• better context for guest mode
• improve notification_list_item_widget.dart: perform notification actions as pleroma async operation without blocking dialog

Fixes

• fix version url in about_page.dart
• guest mode fixes for media
• fix push notifications on mastodon
• fix async_dialog.dart: don't crash when performing async operation without actual dialog
• edit_timeline_settings_dialog.dart: don't listen provider in button callback
• handling sharing intents: better check for oauth callback