docs: update reference documentation for SelectionInput.DROPDOWN to include dynamic data sources and autosuggestion (#32413)

feat: Addition of QuoteType enum, QuotedMessageSnapshot & ForwardMetadata in the QuotedMessageMetadata proto

PiperOrigin-RevId: 864426372

Source-Link: googleapis/googleapis@66d47db

Source-Link: googleapis/googleapis-gen@4cfb0bd
Copy-Tag: eyJwIjoiZ29vZ2xlLWFwcHMtY2hhdC12MS8uT3dsQm90LnlhbWwiLCJoIjoiNGNmYjBiZGY2NjlkMzliOTNmNGViNzNlODk5ZDJkNGQ1NWRmMjFlMSJ9

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* docs: update reference documentation for `SelectionInput.DROPDOWN` to include dynamic data sources and autosuggestion


PiperOrigin-RevId: 864941572

Source-Link: googleapis/googleapis@2ca9449

Source-Link: googleapis/googleapis-gen@2801688
Copy-Tag: eyJwIjoiZ29vZ2xlLWFwcHMtY2hhdC12MS8uT3dsQm90LnlhbWwiLCJoIjoiMjgwMTY4ODZmZWQzYTI0ZGZlMTE2MjI1MzJhMjAyN2EzZDc5MTE3NyJ9

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: gcf-owl-bot[bot]

google-apps-chat-v1/lib/google/chat/v1/message_pb.rb

@@ -1386,6 +1386,26 @@ module SelectionType
             SWITCH = 2
 
             # A dropdown menu. Users can select one item from the menu.
+            #
+            # For Google Chat apps, you can populate items using a dynamic data source
+            # and autosuggest items as users type in the menu. For example, users can
+            # start typing the name of a Google Chat space and the widget autosuggests
+            # the space. To dynamically populate items for a dropdown menu, use one of
+            # the following types of data sources:
+            #
+            #  * Google Workspace data: Items are populated using data from Google
+            #    Workspace, such as Google Workspace users or Google Chat spaces.
+            #  * External data: Items are populated from an external data
+            #    source outside of Google Workspace.
+            #
+            # For examples of how to implement dropdown menus for Chat apps, see
+            # [Add a dropdown
+            # menu](https://developers.google.com/workspace/chat/design-interactive-card-dialog#dropdown-menu)
+            # and [Dynamically populate drop-down
+            # menus](https://developers.google.com/workspace/chat/design-interactive-card-dialog#dynamic-dropdown-menu).
+            #
+            # [Google Workspace add-ons and Chat
+            # apps](https://developers.google.com/workspace/extend):
             DROPDOWN = 3
 
             # A menu with a text box. Users can type and select one or more items.