Bump typespec-client-generator-core to 0.68.4 in emitter-package.json (#27140)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: tadelesh <1726438+tadelesh@users.noreply.github.com>

Author: Copilot

eng/emitter-package-lock.json

@@ -9,7 +9,7 @@
     "@azure-tools/typespec-azure-portal-core": "0.68.0",
     "@azure-tools/typespec-azure-resource-manager": "0.68.0",
     "@azure-tools/typespec-azure-rulesets": "0.68.0",
-    "@azure-tools/typespec-client-generator-core": "0.68.3",
+    "@azure-tools/typespec-client-generator-core": "0.68.4",
     "@azure-tools/typespec-liftr-base": "0.14.0",
     "@typespec/compiler": "1.12.0",
     "@typespec/events": "0.82.0",