chore: reverts addition to ruleset

Author: baywet

csharp/ql/src/codeql-suites/csharp-security-and-quality.qls

@@ -51,7 +51,6 @@
       - cs/linq/inconsistent-enumeration
       - cs/linq/missed-all
       - cs/linq/missed-cast
-      - cs/linq/missed-firstordefault
       - cs/linq/missed-oftype
       - cs/linq/missed-select
       - cs/linq/missed-where