unnecessary codes in sub_mapping.cpp

[deliangye]

Describe the bug The codes section: https://github.com/koide3/glim/blob/master/src/glim/mapping/sub_mapping.cpp#L127-L153 seems not needed since its output is not used for other parts, or we miss something to let its output to be used, right?

--Deliang

[koide3]

Ah, the subsequent computation imu_rate_trajectory should have forgot using the optimized poses. I'll fix it later. Thanks!