SongChiyoung

## Why are these changes needed? Multimodal message fill context with other routine. However current `_set_empty_to_whitespace` is fill with context. So, error occured. And, I checked `multimodal_user_transformer_funcs` and I found...

autogen-ext test is too slow...!

2

### What happened? **Describe the bug** Check each tests at autogen-ext autogen-ext/cache_store : 0.15s autogen-ext/code_executors : 203.89s autogen-ext/memory : 12s autogen-ext/models : 37s autogen-ext/tools: 14s autogen_ext/*.py : 146.02s I could...

Some Team/Agent like SocietyOfMindAgent is trying to use multiple/separated system messages, but the current system does not allow that.

5

### What happened? **Describe the bug** Some Team/Agent like `SocietyOfMindAgent` or ~`SelectorGroupChat`~ tries to use multiple or separated `system_message`s, but the current system doesn't support that. As a result, non-OpenAI...