I don't see a proper place to do this in the 2.0.0 IDE preferences. However, modifying the .arduinoIDE/setting.json file to include "editor.lineNumbers": "off", seems to work.
{ "editor.lineNumbers": "off", "editor.fontSize": 14, ... } 
Edgar Bonet pointed out in a comment that there's still a bunch of empty space in that region. The image above doesn't do a good of showing why though. In the below screenshots I've told the IDE to set a breakout and hovered over where folding region so it displays the fold indicators to make somewhat easier to see that and compare what effect on width results from disabling these things.
If you want to save a bit more space you can add turn off the code folding feature, which removes the spaced that would be used for fold indicators with an additional "editor.folding": "false", in the settings.json file.
For comparison, here's everything enabled, numbers but no folding, folding but no numbers, no folding and no numbers:
I haven't yet found out how to turn off the display of break-point indicators. I assume that it is possible though.