cli[minor]: fix import path for two Astra DB classes in the migration…

… json data (langchain-ai#21926)

This PR fixes two mistakes in the import paths from community for the
json data aiding the cli migration to 0.2.

It is intended as a quick follow-up to
langchain-ai#21913 .

@nicoloboschi FYI

libs/cli/langchain_cli/namespaces/migrate/codemods/migrations/astradb.json

@@ -12,11 +12,11 @@
     "langchain_astradb.AstraDBStore"
   ],
   [
-    "langchain_community.cache.astradb.AstraDBCache",
+    "langchain_community.cache.AstraDBCache",
     "langchain_astradb.AstraDBCache"
   ],
   [
-    "langchain_community.cache.astradb.AstraDBSemanticCache",
+    "langchain_community.cache.AstraDBSemanticCache",
     "langchain_astradb.AstraDBSemanticCache"
   ],
   [
@@ -27,4 +27,4 @@
     "langchain_community.document_loaders.astradb.AstraDBLoader",
     "langchain_astradb.AstraDBLoader"
   ]
-]
+]