[config](inverted index)Make inverted_index_ram_dir enable by default(#35094) (#39120)

## Proposed changes

bp #35094

Co-authored-by: Luennng <luennng@gmail.com>

be/src/common/config.cpp

@@ -1039,7 +1039,7 @@ DEFINE_mBool(inverted_index_compaction_enable, "true");
 // Only for debug, do not use in production
 DEFINE_mBool(debug_inverted_index_compaction, "false");
 // index by RAM directory
-DEFINE_mBool(inverted_index_ram_dir_enable, "false");
+DEFINE_mBool(inverted_index_ram_dir_enable, "true");
 // use num_broadcast_buffer blocks as buffer to do broadcast
 DEFINE_Int32(num_broadcast_buffer, "32");