Dimmer and switch connected to outlet to always hot
Simply nut off the green pigtail by itself

Since there's nothing for the ground pigtail to connect to once the dimmer is replaced by a blank faceplate, simply cap it off with a wirenut.

That dimmer should not have been there to begin with

Dimming a standard wall receptacle violates NEC 404.14(E):


  (E) Dimmer Switches. General-use dimmer switches shall
  be used only to control permanently installed incandescent luminaires unless listed for the control of other loads and
  installed accordingly.


and 406.15:


  406.15 Dimmer-Controlled Receptacles. A receptacle supplying lighting loads shall not be connected to a dimmer
  unless the plug/receptacle combination is a nonstandard
  configuration type that is specifically listed and identified
  for each such unique combination.


Your TV is taking a dim view of being dimmed

The dimmer is also what is responsible for the buzzing sound coming out of your TV due to the mains waveform being modified by the dimmer, even at its maximum setting.