VacuumModes.GENTLE and VacuumModes.OFF share value 105 #999

In roborock/data/v1/v1_clean_modes.py, VacuumModes has the same value-alias problem that #990 fixes for WaterModes:

GENTLE = ("gentle", 105)
OFF = ("off", 105)

Two members sharing one value means lookups by value are ambiguous. Suggest applying the same display_name pattern from #990 here so each mode keeps a distinct value.