workspace: Add keyboard shortcuts to close active dock (#30508)

Adds the normal close keybinding for the new Close Active Dock action.

Release Notes:

- N/A

assets/keymaps/default-linux.json

@@ -538,6 +538,7 @@
       "ctrl-alt-b": "workspace::ToggleRightDock",
       "ctrl-b": "workspace::ToggleLeftDock",
       "ctrl-j": "workspace::ToggleBottomDock",
+      "ctrl-w": "workspace::CloseActiveDock",
       "ctrl-alt-y": "workspace::CloseAllDocks",
       "shift-find": "pane::DeploySearch",
       "ctrl-shift-f": "pane::DeploySearch",

assets/keymaps/default-macos.json

@@ -608,6 +608,7 @@
       "cmd-b": "workspace::ToggleLeftDock",
       "cmd-r": "workspace::ToggleRightDock",
       "cmd-j": "workspace::ToggleBottomDock",
+      "cmd-w": "workspace::CloseActiveDock",
       "alt-cmd-y": "workspace::CloseAllDocks",
       "cmd-shift-f": "pane::DeploySearch",
       "cmd-shift-h": ["pane::DeploySearch", { "replace_enabled": true }],