[MC-131508] Cloning signs create unnecessary syntax

The first sign starts out with the following data:

{x: 1145, Text4: "\\{\"text\":\"\"}", y: 20, Text3: "\{\"text\":\"\"}", z: -1265, Text2: "\{\"text\":\"\"}", id: "minecraft:sign", Text1: "\{\"text\":\"hello\"}"}

Clone the first sign, and this is the data of the second sign:

{x: 1142, Text4: "\{\"extra\":[{\"text\":\"\"}],\"text\":\"\"}", y: 20, Text3: "\{\"extra\":[{\"text\":\"\"}],\"text\":\"\"}", z: -1269, Text2: "\{\"extra\":[{\"text\":\"\"}],\"text\":\"\"}", id: "minecraft:sign", Text1: "\{\"extra\":[{\"text\":\"hello\"}],\"text\":\"\"}"}

Clone the second sign, and this is the data of the third sign:

{x: 1141, Text4: "\{\"extra\":[{\"text\":\"\"},\{\"extra\":[{\"text\":\"\"}],\"text\":\"\"}],\"text\":\"\"}", y: 20, Text3: "\{\"extra\":[{\"text\":\"\"},\{\"extra\":[{\"text\":\"\"}],\"text\":\"\"}],\"text\":\"\"}", z: -1271, Text2: "\{\"extra\":[{\"text\":\"\"},\{\"extra\":[{\"text\":\"\"}],\"text\":\"\"}],\"text\":\"\"}", id: "minecraft:sign", Text1: "\{\"extra\":[{\"text\":\"\"},\{\"extra\":[{\"text\":\"hello\"}],\"text\":\"\"}],\"text\":\"\"}"}

If this is done a few more times, the game gets really laggy.