Revert "ShellPkg: Make the USB mouse behavior in 'edit' consistent with 'hexedit'."

Revert "ShellPkg: Make the USB mouse behavior in 'edit' consistent with 'hexedit'."

This reverts commit ee60bd2b6aa473fdff6af3bfc62203ed8ca5c52a and
e36ed7a84b2768443de22371f0aad5cf502328b1.
The two commits enhanced 'edit' to support text selection through
mouse. But the code introduced some bugs resulting the text
selection behavior is not very usable and potentially hang in
certain platforms.

So I'd like to revert them firstly. If there is strong
requirement for the text selection through mouse in 'edit'
I will refine and re-add the code.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni　<ruiyu.ni@intel.com>
Reviewed-by: Jaben Carsey <jarben.carsey@intel.com>