fix: display actual error in picodata connect

Summary

• fix: display actual error in picodata connect
• bump tarantool-sys on top of picodata/tarantool@317a5cc1

Close #392 (closed), #365 (closed)

Ensure that

• New code is covered by tests
• API is documented
• Changelog is up to date
• (if Lua API changed) Lua API version is bumped in luamod.rs
• (if necessary) A follow-up doc issue is created in picodata/docs and linked here