Address review feedback on security knowledge promotion

- do-not-grant-rights-beyond-a-users-entitlement.md: drop the See sample
  reference to a .good.al file that does not exist
- Remove the 'Contributions welcome' boilerplate line from
  compose-permission-sets, prefer-oauth2, and protect-sensitive-data
- protect-sensitive-data-in-temporary-tables: remove the pointless
  DeleteAll on the locally scoped temp buffer in the good sample and
  reword Best Practice to note local buffers are cleaned up automatically
- Drop guard-bulk-operations-with-istemporary from the promotion; it
  stays in the community layer pending a decision on whether it is security

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

community/knowledge/security/guard-bulk-operations-with-istemporary.good.al

@@ -0,0 +1,12 @@
+codeunit 50100 "Order Buffer Helper"
+{
+    procedure ResetStagingBuffer(var OrderBuffer: Record "Sales Header")
+    begin
+        // The helper is designed for a temporary buffer only. Fail loudly
+        // if a caller accidentally passes the real table.
+        if not OrderBuffer.IsTemporary() then
+            Error('ResetStagingBuffer requires a temporary Sales Header; a persistent record was passed.');
+
+        OrderBuffer.DeleteAll();
+    end;
+}