integrations-docs: Remove images of bot type dropdown menus.

Removes images of the bot type dropdown menus for creating new
bots because they are no longer up-to-date and picking an option
from a dropdown does not seem like it would require a screenshot.

templates/zerver/help/include/create-a-generic-bot.md

@@ -1,5 +1,3 @@
 [Create a bot](/help/add-a-bot-or-integration) for
 {{ integration_display_name }}. Make sure that you select
-**Generic bot** as the **Bot type**:
-
-![](/static/images/integrations/bot_types_generic.png)
+**Generic bot** as the **Bot type**.

templates/zerver/help/include/create-an-incoming-webhook.md

@@ -1,5 +1,3 @@
 [Create a bot](/help/add-a-bot-or-integration) for
 {{ integration_display_name }}. Make sure that you select
-**Incoming webhook** as the **Bot type**:
-
-![](/static/images/integrations/bot_types_incoming_webhook.png)
+**Incoming webhook** as the **Bot type**.