Make assistant::QuoteSelection shortcuts work in agent threads (#32270)

Closes: https://github.com/zed-industries/zed/discussions/30626

Release Notes:

- Fixed `assistant::QuoteSelection` default shortcuts (`cmd->` and
`ctrl->`) so they work in Agent threads too (in addition to text threads
and in the Editor pane).

assets/keymaps/default-linux.json

@@ -218,7 +218,6 @@
       "ctrl-enter": "assistant::Assist",
       "ctrl-s": "workspace::Save",
       "save": "workspace::Save",
-      "ctrl->": "assistant::QuoteSelection",
       "ctrl-<": "assistant::InsertIntoEditor",
       "shift-enter": "assistant::Split",
       "ctrl-r": "assistant::CycleMessageRole",
@@ -244,6 +243,7 @@
       "ctrl-shift-j": "agent::ToggleNavigationMenu",
       "ctrl-shift-i": "agent::ToggleOptionsMenu",
       "shift-alt-escape": "agent::ExpandMessageEditor",
+      "ctrl->": "assistant::QuoteSelection",
       "ctrl-alt-e": "agent::RemoveAllContext",
       "ctrl-shift-e": "project_panel::ToggleFocus",
       "ctrl-shift-enter": "agent::ContinueThread",

assets/keymaps/default-macos.json

@@ -252,7 +252,6 @@
     "bindings": {
       "cmd-enter": "assistant::Assist",
       "cmd-s": "workspace::Save",
-      "cmd->": "assistant::QuoteSelection",
       "cmd-<": "assistant::InsertIntoEditor",
       "shift-enter": "assistant::Split",
       "ctrl-r": "assistant::CycleMessageRole",
@@ -279,6 +278,7 @@
       "cmd-shift-j": "agent::ToggleNavigationMenu",
       "cmd-shift-i": "agent::ToggleOptionsMenu",
       "shift-alt-escape": "agent::ExpandMessageEditor",
+      "cmd->": "assistant::QuoteSelection",
       "cmd-alt-e": "agent::RemoveAllContext",
       "cmd-shift-e": "project_panel::ToggleFocus",
       "cmd-shift-enter": "agent::ContinueThread",