Hi,
I believe this isn’t possible. MIDI Parts always follow the tempo because they always behave like if Musical Mode was enabled.
There’s no toggle for Musical Mode for MIDI Parts.
What you can do however is to set the time signature to X/8 instead of X/4.
This will effectively double the metronome tempo click. All is explained here.
As a workaround, you can eventually stretch the MIDI Part with Object Selection Tool - Sizing Applies Time Stretch.