execute_command: do not strip qoutes for cmd_mode
execute_command: do not strip qoutes for cmd_mode

`cmd_mode` performs its own quote stripping for the mode string to
avoid double stripping quotes for `cmd_bindcode` and `cmd_bindsym` in
`config_command` and `execute_command`. Stripping quotes in
`execute_command` for `cmd_mode` will also result in double stripping,
which will cause issues for any mode string with spaces, such as pango
markup.

1ace/sway,ascent12/sway,ascent12/sway,SirCmpwn/sway,1ace/sway,1ace/sway,ascent12/sway