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.bad.al

@@ -0,0 +1,10 @@
+codeunit 50100 "Order Buffer Helper"
+{
+    procedure ResetStagingBuffer(var OrderBuffer: Record "Sales Header")
+    begin
+        // No IsTemporary check. A caller that accidentally passes the real
+        // Sales Header table wipes every sales header in the company with
+        // no prior warning.
+        OrderBuffer.DeleteAll();
+    end;
+}