Inline query result with SwitchInlineQueryChosenChat is offered in channels where the user has no posting permissions

[gramtools]

Checklist
I am reporting an issue in existing functionality that does not work as intended
I've searched for existing GitHub issues
Description
When a bot uses InlineKeyboardButton with switch_inline_query_chosen_chat (with allow_channel_chats=True), the chat picker shows all channels the user is subscribed to — including channels where the user is not an admin and has no posting rights. After selecting such a channel, the inline result appears at the bottom of the screen as if ready to send, but tapping it does nothing. No error is shown.

Expected Behavior
The chat picker should only list channels where the user has permission to post messages. Alternatively, if an unauthorized channel is selected, the app should display an error indicating the user cannot post there.

Actual Behavior
All subscribed channels appear in the picker regardless of user permissions. Selecting a channel where the user cannot post shows the inline query result at the bottom of the chat UI, giving the false impression it can be sent. Tapping the result produces no action and no error feedback.

Steps to Reproduce

1. Use a bot that has an InlineKeyboardButton with switch_inline_query_chosen_chat where allow_channel_chats=True
2. Tap the button — the chat picker opens
3. Notice that channels where you are just a subscriber (not an admin) are listed
4. Select one of those channels
5. The inline result appears at the bottom of the channel view
6. Tap it — nothing happens, no message is sent, no error is shown
   Screenshots and Videos

The worst thing is that a draft remains that cannot be deleted in the list of dialogues.

Environment
Device: iPhone

iOS version: 26.3.1

App version: 12.6.3 (32738)