Fix missing VideoReader imports in FALCONBench and LongVideoBench

[akawincent]

Summary

This PR fixes missing VideoReader imports in two task utilities that call VideoReader(...) during video loading:

• lmms_eval/tasks/FALCONBench/utils.py
• lmms_eval/tasks/longvideobench/utils.py

Both files used VideoReader(...) but only imported cpu from decord. This can raise a NameError when the corresponding code path is executed.

Changes

• add VideoReader to the decord import in FALCONBench
• add VideoReader to the decord import in LongVideoBench

Notes

• this is a minimal fix with no intended behavioral change beyond preventing the missing-import error
• no task logic or sampling behavior was modified

[akawincent]

Hi @Luodian @kcz358 !

This PR fixes an import missing issue, and the code changes are minor.
Would you be willing to do a quick review?
Thanks~

[Luodian]

LGTM — straightforward import fix. Both files use VideoReader() but only imported cpu from decord.