build(deps): bump idna from 3.11 to 3.15 in ContentProcessor

Applies the changes from Dependabot PR #596 onto dev so they reach the dev branch ahead of the upstream PR (which targets main).

Refs: ADO #44960

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

Author: Shreyas-Microsoft

src/ContentProcessor/requirements.txt

@@ -15,7 +15,7 @@ colorama==0.4.6
 coverage==7.13.5
 cryptography==46.0.7
 dnspython==2.8.0
-idna==3.11
+idna==3.15
 iniconfig==2.3.0
 isodate==0.7.2
 mongomock==4.3.0