Unbind/Rebind Minimap Left-Click (ALT+M)

ALT+M toggles the ability to left click on the minimap, but unfortunately I could not find any ways in the HOTKEY settings to unbind or rebind this function. I have a unique keybinding in-game, which allows my thumb and small finger to reach more keys directly without lifting my other fingers from the ability keys. Unfortunately, sometimes I accidentally hit ALT+M, and momentarily I lose the ability to left click on the minimap. What I don't understand, why players can't unbind or rebind this function. We can do this for other keys, why not for ALT+M? I tried binding ALT+M to another function, hoping that I lose the minimap left click, but no luck. When I do this, the ALT+M will perform the new function, but also retains the left click minimap toggle (i.e. performs two tasks at the same time). Please, provide a choice to unbind/rebind minimap left click toggle in the HOTKEY section.