"data modify block" commands affecting sign front_text.color and back_text.color show incorrect errors

[Evtema3]

The following valid data modify block commands error out on the token color:

data modify block -54 -24 9 front_text.color set value "light_gray"
data modify block -54 -24 9 back_text.color set value "light_gray"

The same behavior does not occur for data merge block equivalents:

data merge block -54 -24 9 {front_text:{color:"light_gray"}}
data merge block -54 -24 9 {back_text:{color:"light_gray"}}