feat: Add preference to force container tabs to a workspace with that container set as default (#2095)

This commit introduces a new preference, "zen.workspaces.force-container-workspace", that allows users to control whether container tabs are automatically placed in a dedicated workspace. When enabled, this feature ensures that all tabs from a container are grouped together within a specific workspace.

The following files were modified:

- `src/browser/components/preferences/zen-settings.js`: Added the new preference definition.
- `src/browser/app/profile/zen-browser.js`: Set the default value for the new preference.
- `src/browser/components/preferences/zenTabsManagement.inc.xhtml`: Added a checkbox to control the new preference in the settings UI.

src/browser/components/preferences/zen-settings.js

@@ -1030,4 +1030,9 @@ Preferences.addAll([
     type: 'string',
     default: 'switch',
   },
+  {
+    id: 'zen.workspaces.force-container-workspace',
+    type: 'bool',
+    default: true,
+  },
 ]);