C#: Remove custom rules_dotnet 0.19.2.

Author: michaelnebel

misc/bazel/registry/modules/rules_dotnet/0.19.2-codeql.1/MODULE.bazel

@@ -13,7 +13,6 @@
         "github:bazel-contrib/rules_dotnet"
     ],
     "versions": [
-        "0.19.2-codeql.1",
         "0.21.5-codeql.1"
     ],
     "yanked_versions": {}