fix: add encodings.idna to the denylist [backport 2.9] (#9886)

Backport 185076f from #9873 to 2.9.

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Co-authored-by: Juanjo Alvarez Martinez <juanjo.alvarezmartinez@datadoghq.com>

ddtrace/appsec/_iast/_ast/ast_patching.py

@@ -38,6 +38,7 @@
     "ddsketch",
     "ddtrace",
     "encodings",  # this package is used to load encodings when a module is imported, propagation is not needed
+    "encodings.idna",
     "envier",
     "exceptiongroup",
     "freezegun",  # Testing utilities for time manipulation

releasenotes/notes/asm-avoid-idna-d724dce73afafa93.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    Code Security: add encodings.idna to the IAST patching denylist to avoid problems with gevent.