feat: Paste Components (OLX) into any Unit in Studio (#31969)

* feat: Implement paste button

* chore: improve docs and add tests for python API

* fix: drive-by fix to use a better API for comparing XML

* feat: track which XBlock something was copied from

* feat: add tests

* feat: enable import linter so content_staging's public API is respected

* fix: error seen when trying to paste drag-and-drop-v2 blocks

* fix: use strip_text=True consistently for XML comparisons

* refactor: rename get_user_clipboard_status to get_user_clipboard

* feat: Better error reporting when pasting in Studio

* chore: convert new test suite to pytest assertions

* refactor: push READY status check into the API per review suggestion

* fix: use strip_text=True consistently for XML comparisons

* fix: store "copied_from_block" as a string to avoid Reference field issues

* fix: minor lint error

* refactor: move data types to data.py per OEP-49

cms/templates/container.html

@@ -48,7 +48,8 @@ from openedx.core.djangolib.markup import HTML, Text
             {
                 isUnitPage: ${is_unit_page | n, dump_js_escaped_json},
                 canEdit: true,
-                outlineURL: "${outline_url | n, js_escaped_string}"
+                outlineURL: "${outline_url | n, js_escaped_string}",
+                clipboardData: ${user_clipboard | n, dump_js_escaped_json},
             }
         );
         require(["js/models/xblock_info", "js/views/xblock", "js/views/utils/xblock_utils", "common/js/components/utils/view_utils"], function (XBlockInfo, XBlockView, XBlockUtils, ViewUtils) {