Move nist-sip from ext.jar to voip-common.jar

No component other than voip-common uses it.

Test: basic sanity
Bug: 140872785
Change-Id: Ie8c9a7266d1ed9ea67b43c9267610e236b6e547a
diff --git a/CleanSpec.mk b/CleanSpec.mk
index f311fc8..6a909c0 100644
--- a/CleanSpec.mk
+++ b/CleanSpec.mk
@@ -253,6 +253,7 @@
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/priv-app/DynamicAndroidInstallationService)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/priv-app/DefaultContainerService)
 $(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/app/CaptivePortalLogin)
+$(call add-clean-step, rm -rf $(PRODUCT_OUT)/system/framework/ext.jar)
 # ******************************************************************
 # NEWER CLEAN STEPS MUST BE AT THE END OF THE LIST ABOVE THIS BANNER
 # ******************************************************************